PS3 Networking/Wireless Problem

[dotoko]

Basically when I try take Pro Evo 2010 online it says:

Unable to Transmit on UDP Port 3658
You may need to connect directly to the internet or adjust your connection device i.e. router settings, etc. Assign DMZ, port mapping, configure NAT table, and other router settings to the ps3 system. Individual products may use unique terminology.

I've tried Port Mapping that port to the PS3 but still no luck... Any ideas?

Edit: I am using Airport Express and WPA/WPA2

[Strolls]

... I am using Airport Express and WPA/WPA2

Are you sure you're not using any other kind of router, too? Typically here in the UK one will use an ADSL router of some kind, and the port will need to be forwarded from that to the Airport Express first.