I might not know much about Access, but I've been a Mac user for YEARS.
Access will NOT run on any Macintosh computer using the Macintosh OS. As far as I know there's no programs that can have it work on Mac's so you will probably be out of luck. FileMaker is the "default" database program on the Mac platform, same as Access is on Windows. There might be something around that can convert one to the other, almost worth a look if it's really needed.
One thing to do is check what sort of Mac and what OS that they are using. If the Mac is a newer Intel-based one then you can load Windows on it, and use Access on there. If it's a PPC-based one, it'll never work.