avi to mp4 conversion

Build ffmpeg from the cvs tree  and trying to use it to conver an avi file 
to an mp4 file

ffmpeg -i org.avi org.mp4
FFmpeg version CVS, Copyright (c) 2000-2004 Fabrice Bellard
 configuration:  --enable-mp3lame --enable-libogg --enable-vorbis 
--enable-faac --enable-xvid --enable-a52 --enable-a52 --enable-dts 
--enable-pp --enable-gpl
 libavutil version: 49.0.0
 libavcodec version: 51.9.0
 libavformat version: 50.4.0
 built on Apr 27 2006 09:05:27, gcc: 4.0.2 20051125 (Red Hat 4.0.2-8)
Input #0, avi, from 'org.avi':
 Duration: 00:00:10.0, start: 0.000000, bitrate: 3242 kb/s
 Stream #0.0, 29.97 fps(r): Video: mpeg4, yuv420p, 640x480
 Stream #0.1: Audio: pcm_s16le, 48000 Hz, stereo, 1536 kb/s
Output #0, mp4, to 'org.mp4':
 Stream #0.0, 29.97 fps(c): Video: mpeg4, yuv420p, 640x480, q=2-31, 200 
kb/s
 Stream #0.1: Audio: aac, 48000 Hz, stereo, 64 kb/s
Stream mapping:
 Stream #0.0 -> #0.0
 Stream #0.1 -> #0.1
[aac @ 0x83d3768]libfaac doesn't support this output format!
Error while opening codec for output stream #0.1 - maybe incorrect 
parameters such as bit_rate, rate, width or height

any IDeas - why this won't work? and what needs to change