急問： one question about H1B transfer

Currently, I am changing my job from company A to company B. Today, we just get the approval notice for H1B transfer which says I can began the employment with new company from 12/08/2008. But actually my start date with new company is 12/22/2008 and my planned last day with old company is 12/19/2008. Based on the approval notice, does this mean I have to quit my old company now??

I worry about this a little and thanks anyone for help!!!