I keep getting this error and a KDE crash in dolphin.

Executable: dolphin PID: 26793 Signal: 11 (Segmentation fault)

It only happens after I open a video file and then close Dolphin. Is there a quick fix for it? Or perhaps I need to change a setting?

If you are not using KDE 4.4, please update.
Otherwise, please install debugging symbols, and file a bug report at bugs.kde.org.