I'm being harassed by someone via PMs in one of my games, and the GMs have to this point not done anything about it.  Is there a way to block the PMs from him?  I'd rather enjoy the game, but it's becoming increasingly difficult from the unwanted communication.

There is no way for you to block messages from another player, no.

The GMs are responsible for handling all in-game disputes, so you will need to ask them to deal with it.  Tell the GMs that this is becoming an issue, and warn them that, if they don't deal with it soon, you would like to be removed from the game.

I would also suggest simply not reading any PMs that you don't want to read in the meantime.

I understand. Thank you both very much!