I solved my last remaining problem as well. Apparently the solpart menu uses a lot of caching... this is what i did:
* problem: image directory of forum solpart menu pointing to old skin name (namely dotnenukeSilver) in new themes folder
* set the forum skin to Dotnetnuke
* copied the dnnsilver dir to dotnetnukesilver
* refreshed page... et voila: image dir of solpart image dir points to dotnetnuke now
* deleted dotnetnukeSilver dir
* changed forum skin to dnnsilver
* solpart image dir still points to dotnetnuke.... is this a caching problem of some sort?
cheers,
erik