Actually the poll makes perfect sense given the time (October) and the fight over the deficit cap and the associated headlines.
For the TEA party, media outlets were reporting a hard line of shut everything down - resulting in a threat from Obama to withhold social security checks.
GOP wise People were (still are) still seething over the deal and view what happened as a form of betrayal. The result was a negative kick back.
If it is one thing we have to worry about in 2012 it is sitting at home and splitting the vote. My guess is that Democrats are planning on it.