Hi I use psx4m without gui and working without problems,but almost games i playing without sound,maybe is having problems with reproduction on some formats on media palyer,if you want to try here is how:
firs remove previous version of psx4m-gui
downloading from here the first file(psx4m_0.4.2_armel.deb) http://maemo.jacekowski.org/mirror/r.../free/p/psx4m/
install to n900(dpkg -i ....)
downloadin from here http://dox.bg/files/dw?a=27ff4f8941 (scph1001.bin) move to n900 MyDocs
create symlink
ln -s /opt/maemo/usr/games/psx4m /usr/bin/psx4m
create folder for games for example Games(cd MyDocs>mkdir Games)
downloading some game from somewhere(bin, iso and img files)
put the game file into MyDocs/Games
start emulator with
psx4m -runcd /home/user/MyDocs/Games/the name of the game
for more options of psx4m type
psx4m --help
you will see several options how to play games,of course how to play without sound
psx4m -runcd -nosound /home/user/MyDocs/Games/the name of the game
regards

I use these 2 links to downloading games:
http://www.emuparadise.me/roms/psx/
http://thepiratebay.se/search/psx%20%20iso/0/99/0