Hello:
I think that there is a issue with a reference in the subtotal formula or in
the column of data.
Try this (from the help pages)
On the Formulas tab, in the Formula Auditing group, click the arrow on the
Error Checking in-group button, point to Circular References, and then click
the first cell listed in the submenu.
Tip You can move between cells in a circular reference by double-clicking
the tracer arrows.
Review the formula in the cell. If you cannot determine whether the cell is
the cause of the circular reference, click the next cell in the Circular
References submenu.
Note The status bar displays the word "Circular References" followed by a
reference to one of the cells contained in the circular reference.
Continue to review and correct the circular reference until the status bar
no longer displays the word "Circular References."
