Would you please show us you reports in design mode?  They #Type! is indicating that the data type is being changed in the calculation.

While it may look ok and display ok in the one as text if you are doing any calculations it needs to be a number data type.
The culprit could be formatting changing it.  With out seeing it, it is difficult to tell based on what you provided.

PreTop is the name of the calculated field and it is set as a Number, double .

The main report decides how you should reference the controls.  If you change the main report, as you did from rpt2a to rpt1, the references likely have to be changed, and that may be why you get the errors.  For instance:

If rpt2a is the main report and rpt2b the subform, a control in rpt2b is referenced as:

     rpt2a!rpt2b.Report!Control1

But if rpt1 is the main report, rpt2a the subform, and rpt2b the subform inside rpt2a, then the same control in rpt2a should be referenced as:

     rpt1!rpt2a!rpt2b.Report!Control1

Check if this is the reason for the error.

That was the issue Kevin, thanks so much for you help!
Also thanks Scott for telling me the info needed!