Filtering or Sorting columns causes message: enter parameter value .fileURL

In Access 2010 I recently got an error when sorting a column or opening a Form that had a sorted column. It was a popup like you would see when you had a missing parameter in a query. It read qryQuery,FieldName.FileUrl and a place to enter the value. It had me stumped so I opened the form in design and removed any sorting. I was then able to open the form OK, but when I clicked on the first column to sort it gave me this error. BTW it was a Split Form with the Datagrid on the bottom and only the Form section on top was editable.

I did a manual Compact and Repair and the then the issue disappeared. Funnily enough this also happened in the compiled ACCDE. So to fix the ACCDE I just did a manual Compact and Repair ACCDB and THEN made the ACCDE. Then it worked fine.

I hope this helps someone else out there one day!