*I have not tested the above links but seemed like good solutions for those who might be interested.
I encountered the following error when trying to install Final Cut Express 3.5 on Lion.
You can't open the application .mpkg because PowerPc applications are no longer supported.
This problem seems to happen when you are using new version of OSX such a Lion(10.7) and Snow Leopard (10.6).
During my quest to find an answer to resolve this I found many people had the same problem with other applications as well. I assume this should work with other applications but have not tested other than Final Cut Express 3.5.