TMPG can't open file

[jmes]

I recently acquired a few AVI files that I am trying to convert to MPG. Windows Media play can view them. VirtualDub can open them (and convert to a AVI that I then could convert to MPG), but TMPG can't open. When I use the "Project Wizard" to open any of the files, I get a "<FILENAME> can not open, or unsupported." error. I have all the latest codecs. Could it be that TMPGE doesn't use external codecs? Any thoughts on how to get them open?

thx in advance