I've been talking up Vegas and telling everyone how great it is, but guess what, there are lots of bugs. Here's another one.
In After Effects, I rendered out an uncompressed AVI movie @ 720x480, so I could bring it into Vegas for DV encoding. (M$ and Quicktime DV codecs suck.) This resulted in a file that is almost 3GB, sitting on an NTFS Firewire drive under Win2K SP2.
When I brought the uncompressed AVI into Vegas, Vegas couldn't read it properly. After about a minute of runtime the picture turned to black. After Effects, Premiere, and Windows Media Player 9 could all read the file correctly. So Vegas is sorely lacking in BASIC FUNCTIONALITY!
Re-rendered the movie as uncompressed Quicktime and brought it into Vegas, now it works.
Thanks for wasting my time.