mplayer installed without libfaac?

[Elizabeth]

im trying to convert videos to mp4 format, but each time i try it says:
>> Command executed:
mencoder -v -noskip -mc 0 -vfm ffmpeg -vf scale=480:320,harddup -oac faac -faacopts br=128:mpeg=4:object=2:raw -ovc lavc -lavcopts vglobal=1:vcodec=mpeg4:vbitrate=700:autoaspect:aglobal=1 -of lavf -lavfopts format=ipod -o "/home/liz/Videos/Portal_Walkthrough.mp4" "/home/liz/Videos/Portal_Walkthrough.avi"

>> Result:
MEncoder svn r34540 (Ubuntu), built with gcc-4.7 (C) 2000-2012 MPlayer Team
MPlayer was compiled without libfaac. See README or DOCS.
MPlayer was compiled without libfaac. See README or DOCS.

i dont know what to do about this, all dependencies are satisfied.
this is an amazing program, everything i need in one program, but it has to work (duh) and it doesnt