I had this problem in Opera. If you're using Opera, right click outside the flash part of the page, click 'Edit site preferences', in that window, go to 'Network', and on the bottom there will be an option that says 'Browser Identification'. Select 'Mask as Internet Explorer'.
The thing about Opera is that will support just about any webpage, but web developers get lazy and don't want to 'develop' for it. So rather than double check that their site works with Opera, which only makes up 2% of the browser share, they'll just skip it entirely, and say their site 'doesn't work' with Opera. If you mask it as IE or Firefox, it will work with sites that say they don't support Opera.