> My ThumbsPlus v9 seems to just skip over these files when making thumbnails. I tried to add 3gp to the File Types list with the Equivalent To as "mpg - MPEG" video, but it did not work. :-(
Equivalent to MPG is fine, but your Windows system needs a codec such as the [link=http://www.codecguide.com/download_kl.htm]K-Lite pack[/link] or [link=http://ffdshow-tryout.sourceforge.net/]FFDShow Tryouts[/link] to decode them (ThumbsPlus relies on Windows to do the decoding, and Windows relies on a codec).
See also this thread from someone who had the same problem with a different movie file format:
http://forums.cerious.com/forum/index.php?id=3452 (and note the warning there about possible undesired software that may be optionally installed with K-Lite when you download it from a less than reputable site - I hope, but don't know for sure, that the official K-Lite distribution site linked above offers a clean installer).