CANNOT install Mac Office 2011 !! Help PLEASE

I have wasted 5 hours on this tonight. I really hope someone can help me. I am running a powerbook 15.4" on Lion. I purchased Mac Office 2011 via download today. I got the DMG file and when it opens and verifies there is an error. If I click 'skip' it gets past this error and I can access the installer. However, when I install, it goes to about 50% through then suddenly changes to 'cleaning up' and I get the following message: 'The installation failed. The installer encountered an error that caused installation to fail. Contact the software manufacturer for assistance.'

What the eff is going on here? I have searched 500 different ways on Google. I have tried starting in safe mode...this still leads it to fail. One thing I will say is when the computer turns on and I hear the sound, I hold down shift. I get the spinning gear with progress bar, however the computer loads up before the progress bar completely fills.

How can I fix this?! I just paid 150 dollars for this software. PLEASE someone help me out here.

Thanks so much in advance