Help! H-1B Transfer: start to work upon Receipt Notice hoard-stocks2011-04-14 19:07:20

but on the approval notice, the valid date is started from a day that is 3 months later than the Receipt day. As I wrong again?! Let's say, Receipt Notice day is 02/02/2011, the valid date on Approval Notice is from 04/18/2011 to 04/17/2014. Was I illgal during the period (02/02/2011 - 04/17/2011) to work?!