Troubleshooting Problem Installing Sims2...help anyone?

Problem Installing Sims2...help anyone?

Everytime I try opening the Sims2 file on the disc it tells me that the Sims2 needs at least 1MB of free space on the hard disk and that I have to free up some space and try again. I've got over 12GB of free space, and the box says you only need 3GB of free space to install and run the game, but it keeps telling me I need 1MB. Anyone know what I should do?

P.S. My computer's an iBook G4, if that's at all important. Thanks in advance for any help anyone can give!