I've had this intermittently too. From previous discussions wiuth skuzzy, it apparently is a known bug realted to AMD processors -- and they havent had an adequate work around for the processor flaw in that situation.
However, I have an Intel 2.6 GHz processor. I'd be interested in knowing if you do too.
I've found the problem will disappear in one of two ways:
1) sometimes its a simple matter of exitng and reentering the program. It may also respond to a system reboot.
2) More often, i seem to run into the problem when I use nonstandard offline maps -- for example, if I change the offline arena map to FinRus or something. In those cases, I just need to change the map. (Which does require a game restart anyway.)
Incidentallly, I had the problem crop up again after the server connect problem too. I cant imagine there'd be a connection, but it is kinda weird that we both ran into it....