The attached file was the content of vim /var/lib/apt/lists/archive.ubuntu.com_ubuntu_dists_natty_main_i18n_Translation-en .

Here's the error message of apt-get:

pacaud@lappc-p348:~$ sudo apt-get update
[sudo] password for pacaud: 
Sorry, try again.
[sudo] password for pacaud: 
Ign http://archive.canonical.com natty InRelease
Ign http://archive.ubuntu.com natty InRelease
Ign http://archive.ubuntu.com natty-updates InRelease                  
Ign http://archive.ubuntu.com natty-security InRelease                 
Réception de : 1 http://archive.canonical.com natty Release.gpg [198 B]
Ign http://archive.ubuntu.com natty-proposed InRelease                 
Ign http://archive.ubuntu.com natty-backports InRelease
Réception de : 2 http://archive.ubuntu.com natty Release.gpg [198 B]   
Réception de : 3 http://archive.canonical.com natty Release [5 916 B]  
Réception de : 4 http://archive.ubuntu.com natty-updates Release.gpg [198 B]
Réception de : 5 http://archive.ubuntu.com natty-security Release.gpg [198 B]
Réception de : 6 http://archive.ubuntu.com natty-proposed Release.gpg [198 B]
Réception de : 7 http://archive.ubuntu.com natty-backports Release.gpg [198 B]
Réception de : 8 http://archive.canonical.com natty/partner amd64 Packages [4 393 B]
Réception de : 9 http://archive.ubuntu.com natty Release [39,8 kB]             
Ign http://archive.canonical.com natty/partner TranslationIndex        
Réception de : 10 http://archive.ubuntu.com natty-updates Release [23,2 kB]
Réception de : 11 http://archive.ubuntu.com natty-security Release [23,2 kB]   
Réception de : 12 http://archive.ubuntu.com natty-proposed Release [23,2 kB]   
Réception de : 13 http://archive.ubuntu.com natty-backports Release [23,2 kB]  
Réception de : 14 http://archive.ubuntu.com natty/main Sources [864 kB]        
Ign http://archive.canonical.com natty/partner Translation-fr_FR               
Ign http://archive.canonical.com natty/partner Translation-fr       
Ign http://archive.canonical.com natty/partner Translation-en
Réception de : 15 http://archive.ubuntu.com natty/restricted Sources [4 117 B]
Réception de : 16 http://archive.ubuntu.com natty/universe Sources [4 381 kB]
Réception de : 17 http://archive.ubuntu.com natty/multiverse Sources [155 kB]  
Réception de : 18 http://archive.ubuntu.com natty/main amd64 Packages [1 557 kB]
Réception de : 19 http://archive.ubuntu.com natty/restricted amd64 Packages [9 027 B]
Réception de : 20 http://archive.ubuntu.com natty/universe amd64 Packages [6 010 kB]
Réception de : 21 http://archive.ubuntu.com natty/multiverse amd64 Packages [180 kB]
Ign http://archive.ubuntu.com natty/main TranslationIndex                      
Ign http://archive.ubuntu.com natty/multiverse TranslationIndex                
Ign http://archive.ubuntu.com natty/restricted TranslationIndex                
Ign http://archive.ubuntu.com natty/universe TranslationIndex                  
Atteint http://archive.ubuntu.com natty-updates/main Sources                   
Atteint http://archive.ubuntu.com natty-updates/restricted Sources             
Atteint http://archive.ubuntu.com natty-updates/universe Sources               
Atteint http://archive.ubuntu.com natty-updates/multiverse Sources             
Atteint http://archive.ubuntu.com natty-updates/main amd64 Packages            
Atteint http://archive.ubuntu.com natty-updates/restricted amd64 Packages      
Atteint http://archive.ubuntu.com natty-updates/universe amd64 Packages        
Atteint http://archive.ubuntu.com natty-updates/multiverse amd64 Packages      
Ign http://archive.ubuntu.com natty-updates/main TranslationIndex              
Ign http://archive.ubuntu.com natty-updates/multiverse TranslationIndex        
Ign http://archive.ubuntu.com natty-updates/restricted TranslationIndex        
Ign http://archive.ubuntu.com natty-updates/universe TranslationIndex          
Atteint http://archive.ubuntu.com natty-security/main Sources                  
Atteint http://archive.ubuntu.com natty-security/restricted Sources            
Atteint http://archive.ubuntu.com natty-security/universe Sources              
Atteint http://archive.ubuntu.com natty-security/multiverse Sources            
Atteint http://archive.ubuntu.com natty-security/main amd64 Packages           
Atteint http://archive.ubuntu.com natty-security/restricted amd64 Packages     
Atteint http://archive.ubuntu.com natty-security/universe amd64 Packages       
Atteint http://archive.ubuntu.com natty-security/multiverse amd64 Packages     
Ign http://archive.ubuntu.com natty-security/main TranslationIndex             
Ign http://archive.ubuntu.com natty-security/multiverse TranslationIndex       
Ign http://archive.ubuntu.com natty-security/restricted TranslationIndex       
Ign http://archive.ubuntu.com natty-security/universe TranslationIndex         
Atteint http://archive.ubuntu.com natty-proposed/restricted amd64 Packages     
Atteint http://archive.ubuntu.com natty-proposed/main amd64 Packages           
Atteint http://archive.ubuntu.com natty-proposed/multiverse amd64 Packages     
Atteint http://archive.ubuntu.com natty-proposed/universe amd64 Packages       
Ign http://archive.ubuntu.com natty-proposed/main TranslationIndex             
Ign http://archive.ubuntu.com natty-proposed/multiverse TranslationIndex       
Ign http://archive.ubuntu.com natty-proposed/restricted TranslationIndex       
Ign http://archive.ubuntu.com natty-proposed/universe TranslationIndex         
Atteint http://archive.ubuntu.com natty-backports/restricted amd64 Packages    
Atteint http://archive.ubuntu.com natty-backports/main amd64 Packages          
Atteint http://archive.ubuntu.com natty-backports/multiverse amd64 Packages    
Atteint http://archive.ubuntu.com natty-backports/universe amd64 Packages      
Ign http://archive.ubuntu.com natty-backports/main TranslationIndex            
Ign http://archive.ubuntu.com natty-backports/multiverse TranslationIndex      
Ign http://archive.ubuntu.com natty-backports/restricted TranslationIndex      
Ign http://archive.ubuntu.com natty-backports/universe TranslationIndex        
Réception de : 22 http://archive.ubuntu.com natty/main Translation-fr [357 kB] 
Réception de : 23 http://archive.ubuntu.com natty/multiverse Translation-fr [60,4 kB]
Réception de : 24 http://archive.ubuntu.com natty/restricted Translation-fr [2 553 B]
Réception de : 25 http://archive.ubuntu.com natty/universe Translation-fr [638 kB]
Ign http://archive.ubuntu.com natty/main Translation-fr_FR                     
Ign http://archive.ubuntu.com natty/main Translation-en                        
Ign http://archive.ubuntu.com natty/multiverse Translation-fr_FR               
Ign http://archive.ubuntu.com natty/multiverse Translation-en                  
Ign http://archive.ubuntu.com natty/restricted Translation-fr_FR               
Ign http://archive.ubuntu.com natty/restricted Translation-en                  
Ign http://archive.ubuntu.com natty/universe Translation-fr_FR                 
Ign http://archive.ubuntu.com natty/universe Translation-en                    
Ign http://archive.ubuntu.com natty-updates/main Translation-fr_FR             
Ign http://archive.ubuntu.com natty-updates/main Translation-fr                
Ign http://archive.ubuntu.com natty-updates/main Translation-en                
Ign http://archive.ubuntu.com natty-updates/multiverse Translation-fr_FR       
Ign http://archive.ubuntu.com natty-updates/multiverse Translation-fr          
Ign http://archive.ubuntu.com natty-updates/multiverse Translation-en          
Ign http://archive.ubuntu.com natty-updates/restricted Translation-fr_FR       
Ign http://archive.ubuntu.com natty-updates/restricted Translation-fr          
Ign http://archive.ubuntu.com natty-updates/restricted Translation-en          
Ign http://archive.ubuntu.com natty-updates/universe Translation-fr_FR         
Ign http://archive.ubuntu.com natty-updates/universe Translation-fr            
Ign http://archive.ubuntu.com natty-updates/universe Translation-en            
Ign http://archive.ubuntu.com natty-security/main Translation-fr_FR            
Ign http://archive.ubuntu.com natty-security/main Translation-fr               
Ign http://archive.ubuntu.com natty-security/main Translation-en               
Ign http://archive.ubuntu.com natty-security/multiverse Translation-fr_FR      
Ign http://archive.ubuntu.com natty-security/multiverse Translation-fr         
Ign http://archive.ubuntu.com natty-security/multiverse Translation-en         
Ign http://archive.ubuntu.com natty-security/restricted Translation-fr_FR      
Ign http://archive.ubuntu.com natty-security/restricted Translation-fr         
Ign http://archive.ubuntu.com natty-security/restricted Translation-en         
Ign http://archive.ubuntu.com natty-security/universe Translation-fr_FR        
Ign http://archive.ubuntu.com natty-security/universe Translation-fr           
Ign http://archive.ubuntu.com natty-security/universe Translation-en           
Ign http://archive.ubuntu.com natty-proposed/main Translation-fr_FR            
Ign http://archive.ubuntu.com natty-proposed/main Translation-fr               
Ign http://archive.ubuntu.com natty-proposed/main Translation-en               
Ign http://archive.ubuntu.com natty-proposed/multiverse Translation-fr_FR      
Ign http://archive.ubuntu.com natty-proposed/multiverse Translation-fr         
Ign http://archive.ubuntu.com natty-proposed/multiverse Translation-en         
Ign http://archive.ubuntu.com natty-proposed/restricted Translation-fr_FR      
Ign http://archive.ubuntu.com natty-proposed/restricted Translation-fr         
Ign http://archive.ubuntu.com natty-proposed/restricted Translation-en         
Ign http://archive.ubuntu.com natty-proposed/universe Translation-fr_FR        
Ign http://archive.ubuntu.com natty-proposed/universe Translation-fr           
Ign http://archive.ubuntu.com natty-proposed/universe Translation-en           
Ign http://archive.ubuntu.com natty-backports/main Translation-fr_FR           
Ign http://archive.ubuntu.com natty-backports/main Translation-fr              
Ign http://archive.ubuntu.com natty-backports/main Translation-en              
Ign http://archive.ubuntu.com natty-backports/multiverse Translation-fr_FR     
Ign http://archive.ubuntu.com natty-backports/multiverse Translation-fr        
Ign http://archive.ubuntu.com natty-backports/multiverse Translation-en        
Ign http://archive.ubuntu.com natty-backports/restricted Translation-fr_FR     
Ign http://archive.ubuntu.com natty-backports/restricted Translation-fr        
Ign http://archive.ubuntu.com natty-backports/restricted Translation-en        
Ign http://archive.ubuntu.com natty-backports/universe Translation-fr_FR       
Ign http://archive.ubuntu.com natty-backports/universe Translation-fr          
Ign http://archive.ubuntu.com natty-backports/universe Translation-en          
14,4 Mo réceptionnés en 19s (729 ko/s)                                         
Lecture des listes de paquets... Erreur !
E: Encountered a section with no Package: header
E: Problem with MergeList /var/lib/apt/lists/archive.ubuntu.com_ubuntu_dists_natty_main_i18n_Translation-en
E: Les listes de paquets ou le fichier « status » ne peuvent être analysés ou lus.