Indeed. GTA1 works pretty well (although waaaaaaaay too fast... you can't drive without hitting something every few seconds ). I've noticed that the iop side returns -1 and 0 for file handle... This means something was wrong, so the iop part has shut down (when checking indirectly from the ee side, it worked and returned proper handle). Try to use new ps2link and load iomanx yourself. I can also post my changed ps2client and ps2link version (iomanx embedded and loaded by default, ps2client has some fixes... but their purpose is the same as the ones used in ps2client version supplied by dlanor).
I remember we had such an issue in the past with dlanor (few years ago). I even had to write a set of simple test apps to diagnose the problem. I just don't remember what was the problem. It was either ps2link or ps2client... I would have to get to my email archive to check this (which is impossible now).