Has anyone found a way to use .avi files using the microsoft MP42 codec in Vegas? I can get them to work fine in Premiere. Vegas 9 treats them as audio-only and Vegas 10 actually just plains says it won't load them. The codec is installed on both computers.

Any ideas?

You may have "a" codec installed but do you have a "VfW" codec installed? Vegas uses "Video for Windows" codecs. Your simplest solution is probably to use some other app to convert it to a format Vegas can read and then edit those files.