PowerPC applications no longer supported MacBook Lion
You will need to use a computer with 10.6 (snow leopard) or earlier if you want to run that software on a Mac. Maybe a friend has an older computer you can borrow. Or maybe it will work on a computer lab machine. 

Other Options:

1) Try running it on a Windows PC (I'm guessing backwards compatibility will be better)

2) Virtual Machine. It looks like Snow Leopard on Virtual Box is very difficult (and I'm guessing illegal) but maybe you can get your hands on a copy of Windows that will work.