Disconnected:Snapshot Error every time i load Nightfall PLR

[.♥. Cupcake .♥.]

I have NO idea what that means, but it always happens when I'm loading into Nightfall PLR. For the past few nights it's appeared for me and disconnects me from the server.
Any suggestions? I've tried clearing the cache and what not (but then my IT knowledge isn't very deep so... this may be a simple fix that I don't know about).

[Bicketybam]

What I would try first is go to Team Fortress in steam, right click and select 'Properties" then go to 'Local Files' and select 'Verify Integrity of Game Cache'.

Let that finish load up TF2 and create a server with Nightfall and see if it creates the error there first. If it doesn't the only other way to test it would be to join a server with the map.

[.♥. Cupcake .♥.]

Thanks for your help I'll go do that now