It means someone recompressed an iMBT XviD avi release to RMVB. Also means that they are lying because RV is lossy so there is no way it is the same quality. My advice is to download the original iMBT release or buy the DVD. That said, it is perfectly possible to convert RMVB files. What exactly is a workable file though?
For the Pocket PC you could use mencoder to create an XviD avi. Could aso use say MeGUI to create an AVC mp4. Plenty of options. For DVD, I'm not sure what I would suggest. Frameserve via AVISynth to your favourite MPEG-2 encoder.