7.4.2 install crash at digirack

Getting kinda worried here. I've been all over the forums, and no one has a solution yet. I'm running os x 10.4.10, and everytime I try to install pt le it crashes when it gets to the digirack. The only info it gives me is that it couldn't install some files, then it tells me to try again.

You need to click the black arrow next to the PRo Tools M-Powered (top most option) to reveal the sub install options at the "custom install screen" where all the check boxes are. Then uncheck digirack and free bomb factory. Now install just the application files and Digi Core audio manager. Once that completes, itll make u restart. Now run installer again and do the reverse. Install only Free BF and Digirack and uncheck the other 2 and it should work. If it's not working, which is rare, then repair disk permissions, check permissions on your Library / app support / Digidesign folder to make sure it's read and write if still not working try doing and OS combo update again or reinstall the OS.

From my understanding 7.4.2 was only designed to work on Leopard...10.5 and above?? maybe digisupport can clear that up.