Final Fantasy VII - Bizzare Problem

I have a clean PSX copy of FF VII I recently bought (greatest hits version) and the game loads completely fine, but my joystick (a usb computer controller) doesnt seem to work with it. It does nothing when you hit the start/O/X buttons. It just keeps cycling through the credits screen. I would think it would be a joystick problem but all buttons and axes are working fine in the control panel and the joystick also works with any other game I've played with ePSXe 1.4/1.6 (such as FF8 etc). Any idea of what this problem i'm having could be? Thank you.