Make sure you have no .x11amp directory in your home
directory.  Invoke x11amp and select a level 3 mp3
file to play, it will dump core.

The problem is that x11amp is not setting itself up
correctly with various defaults if no ~/.x11amp/config
file exists.

So if you start x11amp, and then exit it, x11amp will
create a default ~/.x11amp/config file and this problem
goes away for all future invocations.

The core happens because the mpg123 library is being
passed a null pointer for the ip3_format argument in
function mpg123.c:eval_id3_format.