Converting AVI to MPEG2

[xPafx]

I'm having some problems converting some AVI-files to MPEG2. Been trying for some time to figure out what the problem might be, and it seem to have to do with the frame rate. I keep getting the error "Streaming / Transcoding failed: VLC could not open the encoder." And in the log, verbosity level 2:
avcodec warning: MPEG1/2 does not support 2997003/125000 fps
(mpeg2video@082B96B0)
avcodec error: cannot open encoder

I've tried 2 different AVI-files, one that works and one that doesn't. The difference being as following:
..........................This works.............This doesn't work
Format..................MPEG-4 visual.........MPEG-4 visual
Codec ID................Xvid.....................Xvid
Bit rate.................964 Kbps...............854 Kbps
Width...................640.....................624
Height..................354.....................352
Frame rate.............25.000 fps.............23.976 fps
Writing library.........Xvid 1.1.2.............Xvid 1.2.0 SMP
..........................(UTC 2006-11-01)....(UTC 2006-01-08)

It seems to be the frame rate causing the error, since 2997003/125000 = 23.976. I've also tried changing the preferences: Stream output - Sout stream - Transcode - Video frame rate, from standard 0,00 to i.e. 23976, only receiving the same error message with different numbers (avcodec warning: MPEG1/2 does not support 23972/1 fps). The audio btw. works just fine, and the reason for needing MPEG2 is so that I can watch it on my Dreambox. Streaming to files using another codec also works, at least with DivX2 and WMV, although with WMV the quality is largely reduced. I can also stream to MPEG4, but only after changing the Video frame rate-pref., and the image then is produced in a 5:1-scale or something like that. And anyway the Dreambox can't read the file.

[xPafx]

Finally, after several hours of testing, i've figured this out myself, of course shortly after making the prev.post. Posting it here just in case anyone else might have the same problem. MPEG-1 seems to support only a minor range of frame rates, the lowest beeing 24 and no decimals. So i I set frame rate to f.ex. 24, either under preferences or in the command line (fps=24) it works just fine...