Hi, 
at least the EU Version of LBP2 seems to have this glitch: You are stuck in an infinite loading screen when trying to join a multiplayer session. 
 
Somewhere in the Internet I found a workaround that does the job (at least it works for me). 
 
You simply have to turn off your controller  whenever you are stuck (hold PSN Button down till the menu pops up). Then the level loads and you only have to press the PSN button again to turn the controller back on when LPB2 tells you to do so. 

Does not work.

The US version does that too. It's a real bummer. I'll try it out. Thanks for the heads up.

After playing a few games with some friends today, it does work...most of the time. Hopefully this annoying glitch is patched out soon.

I was just playing with a guy that was in the beta, apparently it's been around since then. You'd think they woulda fixed it by now, but eh.

I havent experienced this bug since 1 day. Perhaps its gone...