I have installed both the 32 bit and 64 bit U12.04 desktops and all is well except for mencoder on the 64 bit desktop I get an error :

[mpeg4 @ 0x7f114895a300]Error, Invalid timestamp=1, last=1

This happens on 64 bit only and works great on 32 bit.

The resulting output file will not start playing, but if I skip past the first few seconds, it will play.

I would like to keep using 64 bit but if I can't find a solution to this problem, I will have to go 32 bit.

Please help if you can.