How to set Commandline Arguments in External Tool

I try to run an external program. My setting is in the attached file.

The only thing i did in a bat file is run dir and redirect to the output file

dir > sheets.txt

The input table has only one line with one cell. It is a fliename.

When I try to run this node, it seems work fine. The input and output file generated correctly.

But the node complains:

ERROR     External Tool     Execute failed: Too few data elements (line: 1 (Row0), source: 'file:/C:/Users/lifej/Desktop/test11/sheets.txt')

What does this mean?