error connecting to server...

As stated, the error reads (the top line in the msg box is cut halfway off, but I think I have it right):

"Disconnect. Pure Server. Client has loaded extra file.
[Game]\materials/dg\dg_blu.vmt
File must be removed to play"

So, I found the file, but it looks like it's supposed to be there.

In tf>materials>dg there are 4 files:

DG_blu.vmt
DG_blu.vtf
dg_red.vmt
DG_red.vtf

Help, advice?

Try deleting them, or moving them out of the materials folder. If they're important, they'll be re-loaded from the .gcf. Do you know what those materials are?

I haven't got the foggiest. I've never manually fiddled with my tf2 files; maybe it's a silly thing I picked up from a customized server?

Anyway, I did nothing, and was later able to connect to your server anyways. If it happens again though, I'm gonna make a backup of those files and just wipe it out and see if that fixes it.