I fixed the problem thanks to the first poster on this site :
http://www.giantbomb.com/playstation...low/35-559107/
Basically do this:
Go to Settings on the XMB, select Network Settings and hit Internet Connection Settings
Click OK, then under 'Select a setting method', select Custom
Choose the type of connection you use.
For Wireless you will then enter the required information for connecting to the WLAN (Network Name and security)
For Wired, we have 'Select the operation mode of the network device.' hit Auto-Detect
Now for 'IP Address Setting,' hit Automatic
For 'Set the DHCP host name,' select Do Not Set
Under DNS Setting, hit Manual
Enter the DNS Server addresses for the DNS server of your choice. It must be exact to connect properly
I used 8.8.8.8 and 8.8.4.4
Hit Automatic for MTU
Hit Do Not Use for Proxy Server
Have UPnP enabled
Hit X to save network settings.
and Done