Hmmm... how odd. I've never bothered with the infiltration mod, but I've used other mods with the mac version, and they work just fine.
Tell your friend to increase Unreal's memory Partition. Like to 110 megs. I've run into memory problems with Unreal before. In fact, they are rather common in net games (when Unreal is set to it's default partition size of 98 megs.) The alternative to increasing Unreal's memory partition is to decrease the detail levels (texture detail, resolution, sound, etc...). But, increasing the memory partition is probably a better solution.
If he doesn't know how to do this (not likely) tell him to do a Get Info (Command I) on the unreal application.
What error/message does your friend get? Knowing this would be very helpfull. /~unreal/ubb/html/smile.gif
Dustin