Version:            (using KDE 4.1.2)
Compiler:          gcc 4.3.1 
OS:                Linux
Installed from:    Gentoo Packages

When one intermixes KDE 3.5 and KDE 4.1 installation and the KDEDIRS variable is incorrectly set, Kopete might fail to open a chat window, due to stylesheet mismatch. This is fine, explaining to the user what the problem is, but instead of producing an useful error message, it just crashes with a SIGABRT.

The steps to reproduce are as follows:
1. Install both KDE 4.1.2 and KDE 3.5.x. Let's say they are installed in /usr/kde/3.5 and /usr/kde/4.1.
2. Set KDEDIRS to something that has /usr/kde/3.5 before /usr/kde/4.1.
3. (the chat window style might play a role in reproducing this, mine's "Clear" with "No_avatars" variant selected)
4. Go online
5. Try to open a chat window with anyone


You can then see this message printed on stderr:
!!!!!!! ERROR !!!!!!! - KHTML default stylesheet version mismatch. Aborting. Check your installation. File used was: /usr/kde/3.5/share/apps/khtml/css/html4.css. Expected STYLE_VERSION 1

And Kopete goes down with SIGABRT. I'll attach a backtrace shortly.