Anybody here ever exceeded 401k contribution limit?

I exceeded the max by a little over $300 despite my efforts to keep it from happening. I think I should contact the plan administrator to get them to refund the excess before April 15. But is there any pain I must go through for tax year 2013 because of this? Is there a special form or somewhere on a schedule I need to report this? Oh, my contributions are roughly 40% Roth and 60% Traditional....

My 1000th post!