I have the same problem i can play the ps2 version fine on the ps3 but get the same issue when i try play it online. I dont understand because pes 6 used to go online with out any probs on my ps3. I think playstation has stopped doing compatibility updates for ps2 games as they stopped backwards compatibility wen they discontiuned 60gb Ps3 models.
I think u r right. I've asked KHAN, one of the members here who play it, and he told me
"hi, i think konami have closed the network play down, as i could not connect anymore with the same message. i think konami want us to play the PS3 version of the game only on the PS3.
anyway hope u got the .psv option file in the forum. coz the ps2 version is still the best gameplay version. u could try pes6 (ps2) on the ps3 for network play it might work."
Too bad for me to here that cuz I bought this version to play online.