Hi,

Exactly what version of Movie Edit Pro (version number, "plus" or classic) are you using and what kind of file are you trying to import (file type/extension)?

If this is an actual *.MP4 or AVCHD file that is encoded in H.264, you'd need to activate the built-in MPEG-4 codec that is part of current Movie Edit Pro versions. However, if this is an AVI file that happens to contain MPEG-4/H.264-encoded video data, which I assume this is, you'd need to install a suitable DirectShow compliant video codec on your system that can handle H.264 decoding. Try ffdshow:

http://ffdshow-tryout.sourceforge.net

I hope this helps.