GTK Apps crash when opening/saving as normal user

[Hackbert]

Binary package hint: gedit

When i try to open/save a file inside a gtk app ( like gedit, openoffice, gimp etc) it crashes with a segvault. When i do this with root privileges, its all fine. I also cant use standard Archiver, but when i use Ark (a kde app) it works.
Also when i add a new User, he can do all fine. I checked the rights of that former user, and everythings ok there ...

Here some terminal messages from
-gedit: ~$ gedit
Segmentation fault (core dumped)

-gimp: ~$ gimp

(script-fu:7722): LibGimpBase-WARNING **: script-fu: gimp_wire_read(): error
Segmentation fault (core dumped)

I didnt find any app thats saying more than gimp while crashing. I did a backtrace for gedit and attched the output. I hope this can help finding a solution to this, since i found a lot bugs/questions about wich where closed due to lack of informaion.

ProblemType: Crash
Architecture: i386
Date: Sun Mar 29 13:39:17 2009
DistroRelease: Ubuntu 8.04
ExecutablePath: /usr/bin/gedit
NonfreeKernelModules: nvidia
Package: gedit 2.22.3-0ubuntu2
PackageArchitecture: i386
ProcCmdline: gedit
ProcEnviron:
 SHELL=/bin/bash
 PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games
 LANG=de_DE.UTF-8
Signal: 11
SourcePackage: gedit
StacktraceTop:
 strchr () from /lib/tls/i686/cmov/libc.so.6
 ?? () from /usr/lib/libgtk-x11-2.0.so.0
 ?? () from /usr/lib/libgtk-x11-2.0.so.0
 ?? () from /usr/lib/libgtk-x11-2.0.so.0
 ?? () from /usr/lib/libgtk-x11-2.0.so.0
Title: gedit crashed with SIGSEGV in strchr()
Uname: Linux 2.6.24-23-386 i686
UserGroups: adm admin audio cdrom dialout dip fax floppy fuse lpadmin plugdev sambashare scanner tape vboxusers video