error code 80130203? NEED HELP!

I have been trying to get on to the PS network but with no joy. Every time i try to log in it comes up with this error. I test my network connection and it comes up with.

Get ip address: Successful
Internet: Successful
PSN: Successful
UPnP: Available
NAT Type: Failed

I have reset router / ps3 and nothing.

I am an active gamer / modder and am stressing out. Can anyone help me?