please provide ur inputs to my posts

First, you cannot use a formula in the Selection Criteria.  The Criteria get evaluated before any formulas do.

Second, um, I'm a little confused as to what you are attempting to achieve.  I mean, if the first due_date is 10/01/2006, then aren't all the other due_dates greater than 10/01/2006 pretty much by definition?

If you want to do complicated self-referential selection criteria like this, you pretty much need to do it in SQL.  Use the SQL Command object to build your data source (where you normally select tables to add to the report, just select Add Command instead).  Here, you can do things like create sub-queries and self-joins to achieve the effect that I think you want.

You may also benefit from using parameters to specify the dates of your report.  It would require the user knowing what the first date is, though.