California EDD Overpayment?

I received an overpayment notice for the second time. The first was an overpayment for months of end of August 2010 till Oct. 2 2010 from an employer I worked part time. I already paid the overpayment and now for the second overpayment notice which was from another employer I am asked to pay for months of late July to mid August of 2010. I am unemployed right now and receving UI benefits. I was not fully aware thatI need to report my earnings even if I work part time. Will I go to jail for this?