I had some issues using the Playstation Media Server application last week and just thought I'd post my own frustrations with the solution.
For a week it was working fine for me in Windows 7 64-bit on one laptop and then in Vista 32-bit on another. Out of the blue it broke and wouldn't work with my PS3 anymore -- as in my PS3 wouldn't see my server running. For the "Status" tab, it showed a big red "X" with the error "No Renderers Found." I wasn't entirely sure what it meant, of course. So I Google'd the issue and didn't find too much help. Just a lot of stuff about AviSynth, making sure Java was allowed through the Firewall, etc, etc.
As it turns out I had to manually go into the General Configuration tab and specify the network interface underneath "Network Settings (Advanced)" and for "Force networking on interface:", I had to choose my wireless card since that was what I was using, of course. And then for "Advanced HTTP and system settings", I had to specific the "Default renderer" which would be "Playstation 3" in my case, and then make sure "Force default renderer" box was checked too. (Also make sure Windows Firewall is turned back on)
So yeah, using System Restore, downgarding the PS3 Media Server program, and re-installing Java didn't help. Just had to manually specify a few things and that was it! So hopefully this post helps someone else out, that's all I have to say, hehe.