OK
I think maybe "Use DivX 4 etc. .." did the trick.
In view of you're not knowing for sure what eventually solved your problem, I won't start to ask you to fiddle around with the overlay-settings etc.
Instead maybe have a look at
this post
Hopefully it helps.
(However, if this does not bring a solution, you will again have to try either select "Use overlay Mode 1" or deselect "Use overlay").