I imagine a lot of your complaints have more to do with your home network, than the PS3 itself. If you're using wireless, try connecting a physical ethernet cable to the PS3 see if that helps alleviate some issues.
Unfortunately, they are not. They Happen both Wired, and Wirelessly, whether I put it on automatically assigned IP, or a static IP in the DMZ, or If I setup a static IP with port forwarding enabled to open the Ports the PS3 Needs.
I don't stream to my PS3, if the media service is enabled, it gives me errors when I try to sign into the psn, try to update games via the psn, or try to do anything related to accessing the PSN. And when I disable media servers, no more errors. I've even disabled my media servers from communicating with the PS3. still no dice.
Trust me, I've looked at my home network up and down, and everything else works without a hitch. Hell, I've even Swapped routers twice. Point is, these errors are not specific to me, so it's not local to my network.