I have just upgraded downlaodd and installed the latest 4.4.1 updates of today 4/3/2010. Now kontact does not start. It just pops up a screen which asks which application kontact should start with and the exists.

This is a critical error as it prohibits any use of Kontact.

Does anybody know how to fix this?

Which distro? How do you start Kontact? Do you have any problems with starting any other applications since the update?