Mariano Gomez has some important information about and incorrect Earned Income Credit value in the 2009 Payroll Tax Update. Mariano includes the info to fix the issue so make sure to read his post if you use Dynamics GP Payroll.
Incorrect EIC Value in 2009 United States Payroll Tax Update
Archived post from 2009. Dynamics GP and the links it points to have changed since; check current documentation before relying on version-specific steps.