Ubuntu One freezes Firefox on startup, slows down computer for about 10-15 seconds

Binary package hint: ubuntuone-client

When I am connected to Ubuntu One and start up Firefox (version 3.5.9) in Ubuntu 9.10, Firefox gets irresponsive and takes at least 15 seconds to load (i.e. it goes grey). During these approx. 15 seconds, CPU usage is very high, normal usage of other programs is not possible anymore. When Firefox finally is loaded and ready to use, the Ubuntu One Icon also disappears, although ubuntuone-client-applet and ubuntuone-syncdaemon are still running.

ProblemType: Bug
.home.rlange..config.ubuntuone.syncdaemon.conf:
 [bandwidth_throttling]
 read_limit = 0
 write_limit = 0
 on = False
.home.rlange..config.ubuntuone.ubuntuone.client.conf:
 [ubuntuone]
 connected = True
 connect = 0
 show_applet = 1
 bookmarked = True
Architecture: i386
Date: Sat Apr 10 16:20:22 2010
DistroRelease: Ubuntu 9.10
Package: ubuntuone-client 1.0.3-0ubuntu1
PackageArchitecture: all
ProcEnviron:
 LANGUAGE=zh_CN.UTF-8
 LANG=zh_CN.UTF-8
 SHELL=/bin/bash
ProcVersionSignature: Ubuntu 2.6.31-20.58-generic
SourcePackage: ubuntuone-client
Uname: Linux 2.6.31-20-generic i686