I'm getting the same problem since friday (2/5). I'm also having the same problem on PS Vita with the code NW-5603-4. Both the PS3 and vita can connect to the network and internet but not Playstation Network!
Tried resetting everything, reconfigured everything, resetting to factory settings, opening ports (80, 443, 465, 983, 3478-3479, 3658, 5223, 10070-10080) and so on! My results... Nothing!
Getting a little frustrated and out of ideas!