Ekka,
I think what you need to do to is convert the MPEG4 format to at least MPEG2 in order for VS10+ to handle it. Ulead may say that the program can do something, however that is probably based on ideal situations.
For example here in the US, new cars being sold have an EPA fuel rating sticker on them. It indicates that the car should get "X" miles per gallon on the highway, and "X" miles per gallon in the city. However in reality that does not happen.
So try to convert your MPEG4 files with this program,
SUPER,
http://www.erightsoft.com/SUPER.html It is a free program that converts about any format to another...
Ron P.