I have exactly the same problem in Orlando using Brighthouse ISP.
Tried 3 PC's, 3 browsers,,,, cleared cache, history and cookies, firewalls & all Antivirus turned off,,,, still get the same blank screen when I try and purchase rapids.
I even tried it on my Wife's 4G verizon phone and no luck.
It's been driving me mad for days,,, Rapidshare tech haven't made any useful suggestions either.