This was a REALLY difficult problem to track down so I am adding it into the world for google to help someone else (or even myself again).
I used one cyrstal report as a basis for another. So I literally copied the report files to a new folder.
When running the report an error was thrown that I could not debug:
Error in File C:\DOCUME~1\Julie\LOCALS~1\Temp\temp_8c3aef3e-caf3-4214-99ee-6ff344a4c8a7.rpt:
Error in formula <Record_Selection>.
'{MDTTests.fieldreportid} = {?Pm-FieldReportswithProject.fieldreportid}
This field name is not known.
What is strange about this error is that the namespace MDTTests is from the original report. So I knew that it was left over somewhere in this report. It took me over an hour to find it. Now it seems obvious and easy to find, I don't know what took me so long to try this

Once in here, I could see the offending code that just needed to be deleted. This is related to linking a sub report but does not show up in the dialog for linking a sub report and it does not get cleared on it's own for some reason. In fact you can see that each time I went to fiddle with this setting through the link sub-report dialog, it just kept adding to the list.

I removed all but the last of these lines and my report came up perfectly.