the Logans tool works like a charm!
I didnt change nothing to my ps3, even tho that i have everything set manual, i just added the proxy server to PS3 and a Firewall rule too PC.
LG5Tool works fine using win 7 ultimate, just had to download a missing library file first.
I managed to reproduce this by renaming the 'update' in the wwwroot dir, so that the ps3-updatelist.txt produces a 404 (The internet check is performed by downloading this file.)
The corresponding connection error is 80028EA8 in my case.
if you get failed internet checking while doing a test, either stop the proxy and start it again and then do a connection test
stop the proxy, turn off the ps3, turn on the ps3 start the proxy and do a connection test