cache error while installing windows 7 on snow leopard

[adardesign]

I am trying to install windows 7 on a Mac OS X (version 10.6) and while it runs the installation i see the windows installation window.
it says that it copied all files (there is a ? meaning that it passed this step)
then it gets stuck (freezes) when it expanding files it gets up to 2% or 6% and then it freezes and after a few minuets i see an error stating that there is an cache error.

What can i do, does someone have experience ?

Thanks tons