If you are logged in but you can't see any videos then you may have a firewall that prevents your access. Firewalls can be stand alone pieces of hardware, software installed on your computer, or settings in your DSL and Cable Modem. While it's rare, you should experiment by turning off your firewall and see if that fixes your issue. If after turning off the firewall, you can view everything normally then you know you will need to make some changes to your firewall settings before turning it back on.
This usually isn't an issue for our home customers, but if you are being naughty and trying to watch porn from your work then you might run into this issue.