Try disabling the 2 firewall settings in the Advanced setup tab, under Firewall. Save and Reboot. At least, It worked for me :)

Region : UnitedKingdom Model : TD-W8961ND Hardware Version : V3 Firmware Version : 3.0.0 Build 120524 Rel.05221 ISP : I have just bought this ADSL router. Of course, the first thing I did was upgrade...