I need to place calculated fields in the report footer of the main report that use fields from the subreport for the calculation. The logical way to do this would be to simply create calculated fields in the footer and write the expression using the desired fields from the subreport. However, for the life of me, I can't get it to work. Any suggestions?

Put a hidden text box in the subreport add your calculation to that text box, set reference to it on another text box in the main report footer.
HTH

I have done as you suggested. The calculation works in the hidden field in the subform. I referenced it in the new text box by using it as the control source. When I run the report, the result of the field in the main report is #Name? Am I missing something here?

Just a thought...I found in the Access Bible (as I affectionately call it) an obscure troubleshooting reference to the #Name? result. It says that this could be a result of the control source having been changed and the change not being reflected in your expression...as a twist on this, could I be getting this result because the main report and subreport have different control sources? If so, is there a work around?