freePBX error in installation

I just finished installing freePBX and when trying to start it I get the following logfile error:

Jul 21 17:27:48 VERBOSE[25913] logger.c: [format_mp3.so]Jul 21 17:27:48 WARNING[25913] loader.c: /usr/lib/asterisk/modules/format_mp3.so: cannot open shared object file: No such file or directoryJul 21 17:27:48 WARNING[25913] loader.c: Loading module format_mp3.so failed!

What should I do? I followed the instruction (http://powerontech.com/freepbx-on-debian.htm) “by the book”.

Thanks a lot!
It works great!

install the addon’s
wget http://ftp.digium.com/pub/asterisk/releases/asterisk-addons-1.2.3.tar.gz

tar -zxvf asterisk-addons-1.2.3.tar.gz
cd asterisk-addons-1.2.3
make clean
make install