Slush's pool, for one, will get these errors up to 20 times per hour. But this has only been going on for maybe 3-4 days at most.
My miners at BTCG experienced far less, and mostly sporadic rpc errors.
yeah, since OP mentioned they were trying to connect to guild i was throwing out most likely guild culprits.
i believe i heard slush's were due to load balancing issues which should be fairly resolved by now?
i really try not to slander any particular pool, since every pool has some pretty serious issues as development furthers.