Having trouble connecting Ad Hoc Party with PSP Games, well your not the only one.
Games Such as Dissidia Duodecim, God Eater, KH BBS, etc. have been experiencing connection issues from the latest PS3 Firmware 4.20 So far the only information I've found on the subject are located here.
I don't know How many Ad Hoc PSP Games are having connection issues but seems like the main problems are with
God Eater Burst.
Dissidia Duodecim Final Fantasy
Kingdom Hearts Birth By Sleep
I'm hoping I can get some more info on it for you all. :/
EDIT: Information with a little more Detail http://community.us.playstation.com/...6493#U37476493