Using the Join tool in ffmpegX results in the audio portion of the second avi joined to be out of sync.
These files were made using the ffmpegX AVI mencoder setting, video size=640 x 352 pixels; audio as mp3 128kbps 48000 hz stereo and this is the same on both clips. I thought I used the XviD Codec but info in Quicktime says they are both DivX. The only difference info in QT shows is that the frame rate in the first is 23.97 & in the 2nd is 23.99.

I do not see any variables to the join tool, how do I correct this?
Why is the first clips audio in sync, but the second clip is out of syn in the resultant joined file?
The second clip source used to make the join is in sync prior to being joined.

ALSO
What is an advisable way to trim an AVI?

ALSO
Every attempt to convert a trimmed QT .mov to an AVI with any CODEC in ffmpegX fails.
One info says:
Opening audio decoder: [mp3lib] MPEG layer-2, layer-3
mencoder(1362) malloc: *** vm_allocate(size=4294578176) failed (error code=3)
mencoder(1362) malloc: *** error: can't allocate region
mencoder(1362) malloc: *** set a breakpoint in szone_error to debug

Why can I not convert these?