Unable to decrypt data

I seem to have lost all the pictures in the rooms of my team speak which have been replaced by a red circle with a line going through it. my notification centre is saying the following,

myTeamspeak notification
Unable to decrypt data please,
apply encryption back up key

All fine and dandy but wtf is this key? Where do I get it? How do I apply it?

TeamSpeak is far too complicated for the self taught non IT person (you know, Joe Public).

Can anyone help me before I throw a beer glass at my computer screen?