I am running a regression using visual basic,

Application.Run "ATPVBAEN.XLA!Regress", Range(Range("poolTbl").Cells(i, 8)), _
Range(Range("poolTbl").Cells(i, 9)), False, False, ,
Worksheets("Result").Cells(myRow, 1), False, False, _
False, False, , False

Things were working fine. But at some point, I started receiving the error:

The macro '' cannot be found

Any idea why this is happening?
Thanks