If upnp did not work, then you should follow these instructions.
The MI424WR Verizon FiOS Router ships with a long list of preconfigured settings for popular applications. If you know the specific port address etc that needs to be opened in the Router. Please go the page titled "How to enable ADVANCED Port Forwarding on the MI424WR Verizon FiOS Router."
There aren't any other setting the actiontec needs. It's either UPNP which allows the ps3 to open ports at will, kind of like port triggering for compatible upnp devices.
or port forward.
if you did one, you shouldn't need to do both. The port forward is a manual way to do what UPNP is trying to accomplish.
What does sony say that code means?
Well always having a service busy error is a bit strange. I have a PS3 and very rarely have issues connecting. I sometimes have issues on Saturdays, but most of the time it connects just fine.
For the OP. The PS3 has been having a lot of issue with the last few updates causing a multitude of issues. Have you tried manually downloading the most current update to a thumb drive and updating the PS3 again? Or tried using the backup utility, formatting the hard drive and then restoring the backup? I recently had several issues with my PS3 (not quite the same as you but similar) where I could not get any downloads from the PS store. I backed up my services to a thumb drive and used my computer to download the most recent update. Then I formatted the PS3 and restored from the thumb drive. Havent had any issues since. It was a hassle and PS3 support was useless, but once done, everything is working again. You may want to try that. May help, may not. YMMV.