I can't seem to get it to work under my installation of Ubuntu 7.10. Here's what I get in the debug console:

OUTPUT>MEncoder 2:1.0~rc1-0ubuntu13.1 (C) 2000-2006 MPlayer Team
OUTPUT>CPU: Intel(R) Core(TM)2 CPU 6600 @ 2.40GHz (Family: 6, Model: 15, Stepping: 6)
OUTPUT>CPUflags: Type: 6 MMX: 1 MMX2: 1 3DNow: 0 3DNow2: 0 SSE: 1 SSE2: 1
OUTPUT>Compiled with runtime CPU detection.
OUTPUT>success: format: 0 data: 0x0 - 0x2b869800
OUTPUT>AVI file format detected.
OUTPUT>VIDEO: [XVID] 640x272 12bpp 23.976 fps 1221.8 kbps (149.1 kbyte/s)
OUTPUT>[V] filefmt:3 fourcc:0x44495658 size:640x272 fps:23.98 ftime:=0.0417
OUTPUT>=========================================== ===============================
OUTPUT>Opening audio decoder: [mp3lib] MPEG layer-2, layer-3
OUTPUT>AUDIO: 48000 Hz, 2 ch, s16le, 128.0 kbit/8.33% (ratio: 16000->192000)
OUTPUT>Selected audio codec: [mp3] afm: mp3lib (mp3lib MPEG layer-2, layer-3)
OUTPUT>=========================================== ===============================
OUTPUT>Opening video filter: [expand osd=1]
OUTPUT>Expand: -1 x -1, -1 ; -1, osd: 1, aspect: 0.000000, round: 1
OUTPUT>Opening video filter: [scale w=480 h=360]
OUTPUT>Opening video filter: [crop w=453 h=272]
OUTPUT>Crop: 453 x 272, -1 ; -1
OUTPUT>=========================================== ===============================
OUTPUT>Opening video decoder: [ffmpeg] FFmpeg's libavcodec codec family
OUTPUT>Selected video codec: [ffodivx] vfm: ffmpeg (FFmpeg MPEG-4)
OUTPUT>=========================================== ===============================
OUTPUT>Forcing output FourCC to 30355844 [DX50].
ERROR>MP3 audio selected.
OUTPUT>VDec: vo config request - 640 x 272 (preferred colorspace: Planar YV12)
OUTPUT>VDec: using Planar YV12 as output csp (no 0)
OUTPUT>Movie-Aspect is 2.35:1 - prescaling to correct movie aspect.
ERROR>SwScaler: reducing / aligning filtersize 5 -> 4
ERROR>SwScaler: reducing / aligning filtersize 5 -> 4
ERROR>SwScaler: reducing / aligning filtersize 5 -> 4
ERROR>SwScaler: reducing / aligning filtersize 5 -> 4
ERROR>
ERROR>SwScaler: BICUBIC scaler, from yuv420p to yuv420p using MMX2
ERROR>SwScaler: using 4-tap MMX scaler for horizontal luminance scaling
OUTPUT>videocodec: libavcodec (480x360 fourcc=30355844 [DX50])
ERROR>SwScaler: using 4-tap MMX scaler for horizontal chrominance scaling
ERROR>SwScaler: using n-tap MMX scaler for vertical scaling (YV12 like)
ERROR>SwScaler: 453x272 -> 480x360
OUTPUT>[VE_LAVC] High quality encoding selected (non-realtime)!
OUTPUT>Pos: 0.0s 1f ( 1%) 0.00fps Trem: 0min 0mb A-V:0.000 [0:0]
OUTPUT>Writing header...
OUTPUT>ODML: vprp aspect is 16384:9830.
OUTPUT>Writing header...
OUTPUT>ODML: vprp aspect is 16384:9830.
ERROR>
ERROR>1 duplicate frame(s)!
OUTPUT>Pos: 0.1s 2f ( 1%) 0.00fps Trem: 0min 1mb A-V:0.004 [0:0]
Return: 139

I've tried different quality settings and it always seems to fail... any ideas?

Thanks!