Any ideas why I'm being banned every now and then from drkpool?

Me or the pool?
Your config file must not be a good setup, your rejects should never ever be above 1.5-2% total.
You are losing money on electricity and losing coins you could have if your set up
Looks like you have 2- 280x's. Correct?
Is so, your intensity is way too high. Most people have their intensity at around 13-15.