I often find the same problem of "The data type is not supported." with many of my divx movies. I discovered that it is generally related to the audio. In many cases, it is fixed if I recode only the audio to MP3 CBR (and "direct stream copy" for video) using VirtualDub.
However, with some movies, when I get the data type error, and convert the audio to MP3 CBR, it result in audio out of sync: this frequently happens when the video starts with silent audio. The workaround that I found are:
a) using the Audio Interleaving option to resync the audio (but sometimes then I get the "The data type is not supported." again)
b) or removing the first few seconds of the movie, until a key frame where video starts with audio. In this case, I have to resync the subtitles, due the missing seconds.
c) or my last option is transcoding the whole video again to a different codec.