i have some rmvb and rm video files, could someone give me some clue how to make the n800 vc could convert rmvb and rm file?

i got these error message in n800 vc(ver 0.8.4.0) console:
CPU: AMD Athlon(tm) 64 Processor 2800+ (Family: 15, Model: 12, Stepping: 0)
Stream description: Audio Stream
Selected audio codec: [ffcook] afm: ffmpeg (FFmpeg COOK audio decoder)
Expand: -1 x -1, -1 ; -1, osd: 1, aspect: 0.000000, round: 1
Read the RealVideo section of the DOCS!

ERROR: Could not open required DirectShow codec drvc.so.