That is what I guessed. I have Seamonkey etc... here. Hmm, should I creat symlink or so and with what?
Yeah, you can do that.
Enter the Seamonkey lib directory first:
Then check what exists in there, with a simple ls
You should see a directory called seamonkey-x.x.x (where x.x.x stands for the version number).
Now simply make a symlink that points to the old directory that avidemux was built against:
ln -s seamonkey-x.x.x seamonkey-1.0.6
Remember to replace x.x.x with the correct value that you saw with the ls