I ran the Aging report for Jan 31,2012 & as well for March 31, 2012. I compared these two reports to the G/L control account for AR and we are fine.
It is when I run the Feb 29 aging where we get the problem. (And note that Feb 29 is less than a month at this time.)

I enabled check history during DIC and reran the check. It completes with no errors.