Two ranges good separatly but not together

XL2010
I've successfully done this with numerous other workbooks but not these two.

Runtime error 1004

wbThis.Worksheets("Sheet1").Range(Cells(LastRowORD, 1), Cells(LastRowORD, LastCol)).Value = wbCSV.Worksheets("Sheet1").Range(Cells(i, 1), Cells(i, LastCol)).Value

The Range is valid because
in the immediate pane with EACH RESPECTIVE WORKBOOK ACTIVE
I can successfully select each half in this manner:

wbThis.Worksheets("Sheet1").Range(Cells(LastRowORD, 1), Cells(LastRowORD, LastCol)).select

wbCSV.Worksheets("Sheet1").Range(Cells(i, 1), Cells(i, LastCol)).select

THANK YOU!
I took all my variables out in case they were causing the problem.
In the past I have used Named Ranges (with Workbook scope) to enter values, which eliminated the need for the seemingly redundant qualifying.