Is this when you try connecting to the internet (or another PSP) ?
This error appears in a google search quite a bit - seems the error is caused by a problem with the WLAN connection (or settings).
Most places i've read say that there is little you can do other than:-
1. Remove ANY custom firmware and ensure you have a clean (1.5?) firmware installed.
2. Remove memory stick
3. setup and test your network settings.
If it still gives an error, it seems the only thing you can do is take it back to $ONY for a replacement. (Apparently $ony don't even know what causes the problem!)
If it's out of warrenty you're stuffed, but if you're good with electronics i guess you could take the PSP apart and have a look to see if anything obvious is damaged (hardware wise).
Don't know if this helps at all, but i thought i'd give it a shot!