Did this process ever work? Or is a new process you are working on?
Just to make sure I'm understanding, the only difference between working and not working is changing the table name from &[Inputfile] to a table name of "REPORT1" or some other string?
Another possiblitiy is to add a calculated field to your Monarch model that contains the file name. There is a macro in Data Pump to use the first value in a column, which would be the same thing as the file name.