Did you try to delete this script step and redo it without using a variable as source. run the script. if it works, after change the script step for giving the variable.
I ran into a similar problem with scripted imports. I couldn't seem to both specify a variable and retain the correct field mapping. I fixed it this way:
I set up the script step explicitly referencing a file by name and selected the import options I wanted to specify a source table and to map fields the way I wanted.
I then edited the External data source entry to be:
Since $PathVariable is listed first, the script would always try to find and open the file specified in it, but now my import options were correctly retained.
That worked great. Similar to the first post, though for my app, this works fine as I check that the other file and path exist before loading a table that contains load information first t. I thought of using the multi file listing before to run through my list, but I wanted to be sure it was always loading from the same file, so this lets me define the table and still load just the file I want. Thank you. -Doug.