For appreciating the help of friends in this forum, especially PJIANG 老师's precious information, I am sharing my depressed then rejoice experience below. Hope it will be helpful for any brother/sister who may encounter similar situation like me.
7/20/08, received denial notices for all I-485 applications of my family based on an approved EB-1(B) I-140 because my EB-1(B) was treated as EB-2 category (so, was thought our priority date not current when filing I-485 forms);
7/21/08, filed out an I-290B motion for reopen and reconsider for myself, and was received on 7/22/08 (by USPS track);
7/22/08, visited district representative in Congressman office of our area. The representative (an extremely nice lady) immediately contacted USCIS for us and promised us that she would take care of our issue as her first priority;
7/23/08, the representative told me by phone that USCIS responsed, realized the mistake and would resolve our cases by the end of this week;
7/24/08, received email messages from USCIS that our cards were ordered;
7/25/08, back to work with my original EAD.
I think my visiting the Congressman representative was a crucial step. Her efforts speed up the resolution.