I have created a Class diagram... The above mentioned error is occuring while exporting it as png image... Reproducible: Always
There are no informations about the version, the environment (OS version, architecture) and how umbrello has been started, so only a few hints can be given. Starting umbrello on windows will autostart kdeinit.exe, which will start klauncher.exe. klauncher.exe is used for load kio_file plugin for saving xmi files. This bug is normally caused by not having klauncher.exe running either caused by issues with autostarting or after a crash. Running dbgview (from sysinternals.com) before starting umbrello.exe may show some more informations. If the problem persists after updating umbrello to a recent version from http://download.kde.org/stable/umbrello/latest/, feel free to reopen the bug with a few
... more informations.