The PSX emulator for the Wii is not good enough. The most games do not work, or has many errors and bugs. But for your question of Alien Resurection, this title is not working.
But I had also try out the Alpha and E3 BETA version, this ISO image is working on the Wii ! The same with FreeMC Boot on the PS2, the final version do not work, but mostly all of the BETA version will work. I can not find any information about this on google, but sometimes the prototype copy can fix it, that make it interessting.