First, try to see if the website works in another browser. If you don't have another browser installed, try google chrome by clicking this link: https://www.google.com/chrome/
If the game plays through Chrome, but you still would rather use Firefox, try updating your adobe flash software as well as Java, as some games use flash on Pogo as well. Pogo also has a scan tool that can scan your computer for compatibility issues. Click this link for it: http://www.pogo.com/system-info
Please reply if you need more help. We offer an additional remote assistance service that will allow me to remote into your computer and fix the issue should you want to go that route.