Can't reset data date, so some items are misscheduled

My problem is that I set the data date at the start of building the schedule, which was after the start of the project.  I have tried to reset the data date prior to the start of the items so that they schedule correctly, but I have not been able to figure it out.  If I go to "Tools _ Schedule" and try to reset the data date, I get a message that says the "Data Date cannot be earlier than Project Planned Start Date".  If I go to "Tools _ Apply Actuals", I get a message that says "The