Afraid I don't know what you mean the function macro opens.

If you are referring to the debug dialogue...
The only way I get the macro to error on that line is by using the wrong file path and then the debug dialogue tells me what the problem is

Run-time error 1004
"J:\Manual POs\Manual PO Log\Manual PO Log2.xlsx" could not be found.

When I use the file path to the file on my own computer, which I know is right, there is no error.
My only guess is your file path is not right.