hey and welcome to the avast forum. have you checked with facebook on this? sens avast have nothing to do with playing games on facebook to do. I play some facebook games and have no problem with it, and been using avast for years.

by the way what games are we talking about here?

have you installed any adblocker like adblockplus this could sometimes block games that uses adds before staring a games but you can right click on the adblock plus and set it to not block this page. could it be this that is your problem?