By now you've either found the solution or given up trying to play on your BlackBerry, but just in case...
In your browser hit the Menu key and then go to Options - Browser Configuration and check you've got the Support JavaScript box ticked. Many sites work better if you set Browser Identification (further down the same page) to 'Firefox', but if you don't want to do that globally then create a bookmark for RHP and edit the preferences for that. If you haven't reset your BlackBerry in a while then a battery-pull won't hurt either.
I hope that helps? These days most of my RHP is played on my BlackBerry. 🙂