iLife 08 install problems

I just got the iLife '08. When I click the packet to intstall I get this message:

The Installer package "iLife '08" cannot be opened.
There was an unknown error with the package (999)

I have never had this happen to me on any other install. What can I do to fix this and get this installed?

Thanks.

Have you talked to apple

problem solved

I found my problem. Tiger wasn't working. Installed Leopard and problem solved. Thanks.