Check the following topic: viewtopic.php?f=1&t=14559&start=195&hilit=captcha
Should still work with AddBlock, but disable it for the test. If you're using a VPN, either switch that off or change servers. Clear your cache and cookies from your browser, then log-in and try again. In that order.
If that works, then the problem is from your end, the site works fine.
Also, if you want, send me your IP through PM so I can check it for restrictions. Do not post that info here for security reasons.
When/if you do, let me know at that point of sending it if you were able to download subs or not. Include info of what browser you were using and if you were using a private IP address or a VPN.