On Suse Im not 100% sure, its has an rpm based package manager. Yast might be able to show whats installed, dont know. There should be some sort of listing in /var/log somewhere.........mine is in /var/log/packages but thats slackware with the pkg system.
rpm istelf might be able to show you, try man rpm in a terminal and see what the man page says about it, I know rpm keeps a database of whats installed so it can resolve dependencies.
other than that, check the Suse website and see what it has in the way of tutorials or help
Im about 90% sure what your lacking is called "libmad" which is an audio mpeg library, but it may be called something else
ftp://ftp.pbone.net/mirror/ftp.gwdg.....1b-0.i586.rpm
that ^^ may or may not fix it.........it should
install that with rpm -i <filename> (I think) then run ldconfig
do both as root, then try to play an mp3