Never heard of -xvfwopts.
Do you just want to encode a DivX 4/5 AVI from the .RM?
If you do, this works 100% fine for me. You'll need libavifile installed though, and the mplayer package compiled to make use of it:
mencoder filename.rm -o filename.avi -oac copy -ovc lavc -ffourcc DX50 -lavcopts vcodec=mpeg4:vbitrate=1200:vrc_eq=tex:naq:ilme:trell:cbp
reme=1:
keyint=132:mbd=0:qns=1:vme=4:dia=2 -noskip
This results in a quite high-quality file (at least high enough for me, maybe not for quality aficonados). It plays 100% find on Windows if you have the DivX codec installed as well, and of course works fine in MPlayer. It creates a DivX compliant .AVI, which seems to be what you want to do?
Regards,