Error reding codec ???

[colinb1]

Hi - I hope someone can help me with this one.

I am using Movie Factory 4 to do some simple editing. When I'd finished,
the film is fine via Ulead but when saved to mpeg according to instructions and viewed via Windows Media Player, there is a message 'error reading codec' and there is no volume on the film.

Any help would be appreciated.

Thanks
Colin