To fix a corrupt mp3 mp3val can be used. The website provides binaries for Windows, and sources for other platforms including Linux and Mac OS X.
Update: binaries for Mac OS X (tested on 10.6) here
To install on a Mac either install it the easy way:
brew install mp3val
or download the sources and then
cd to the directory of sources and then do
make -f Makefile.gcc
and then place the binaries in you
To fix the corrupt mp3s use the following
mp3val to fix the errors in the mp3s. Shell wildcards can be used e.g.
mp3val -f *.mp3
which will fix all mp3 in the current directory.
mp3val also keeps all the old tags as well, which is useful.