lsb_release crashed with ImportError in <module>()

Binary package hint: lsb

got this error after first reboot, after distribution upgrade

ProblemType: Crash
Architecture: i386
Date: Fri Aug 21 06:17:32 2009
DistroRelease: Ubuntu 9.10
ExecutablePath: /usr/bin/lsb_release
InterpreterPath: /usr/bin/python2.6
Package: lsb-release 4.0-0ubuntu2
PackageArchitecture: all
ProcAttrCurrent: unconfined
ProcCmdline: /usr/bin/python /usr/bin/lsb_release -is
ProcEnviron:
 PATH=(custom, user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
ProcVersionSignature: Ubuntu 2.6.31-6.25-generic
PythonArgs: ['/usr/bin/lsb_release', '-is']
SourcePackage: lsb
Title: lsb_release crashed with ImportError in <module>()
Traceback:
 Traceback (most recent call last):
   File "/usr/bin/lsb_release", line 26, in <module>
     import lsb_release
 ImportError: No module named lsb_release
Uname: Linux 2.6.31-6-generic i686
UserGroups: