I upgraded from Ubuntu 8.02 to 8.10 to 9.04 to 9.10.

I made the mistake of not updating the files in 8.10 and 9.04 before upgrading to the next version of Ubuntu. That is probably the cause of the problems. I don't know how to update those files.

I run gnome, but I normally use Kate and Kwrite, which are KDE things. They used to work just fine. Now they don't work.

This is what happens when I try to run Kate:

Application: KBuildSycoca (kbuildsycoca4), signal: Segmentation fault
[KCrash Handler]
#6 0x00e29457 in KSycocaEntry::offset() const () from /usr/lib/libkdecore.so.5
#7 0x0041276f in ?? () from /usr/lib/libkdeinit4_kbuildsycoca4.so
#8 0x0040b45c in ?? () from /usr/lib/libkdeinit4_kbuildsycoca4.so
#9 0x0040e24d in ?? () from /usr/lib/libkdeinit4_kbuildsycoca4.so
#10 0x0040f90f in kdemain () from /usr/lib/libkdeinit4_kbuildsycoca4.so
#11 0x080485cb in _start ()

and:

Application: Kate (kate), signal: Segmentation fault
[KCrash Handler]
#6 0x01dd2aa0 in QDataStream::operator>>(int&) () from /usr/lib/libQtCore.so.4
#7 0x004f397d in KServiceFactory::KServiceFactory() () from /usr/lib/libkdecore.so.5
#8 0x004f3ccc in KServiceFactory::self() () from /usr/lib/libkdecore.so.5
#9 0x004eb0a5 in KService::serviceByDesktopName(QString const&) () from /usr/lib/libkdecore.so.5
#10 0x04ebab10 in KTextEditor::EditorChooser::editor(QString const&, bool) () from /usr/lib/libktexteditor.so.4
#11 0x0067c161 in ?? () from /usr/lib/libkateinterfaces.so.4
#12 0x0066d797 in KateApp::KateApp(KCmdLineArgs*) () from /usr/lib/libkateinterfaces.so.4
#13 0x00ae07a7 in kdemain () from /usr/lib/libkdeinit4_kate.so
#14 0x080485cb in _start ()

Several other KDE-based programs produce a similar error message.

I installed all the KDE stuff in an effort to solve the problem, but that didn't work.

I re-installed Kate, but that didn't work.

How can I solve this problem and make Kate and Kwrite work?

Please ensure that libqt4 and kdelibs5 are at their latest versions.