Yes, I agree that's annoying. If your script imports from a file that isn't open, but which is set up with the same account name and password, the system shouldn't stop with each import and ask for account name and password.
The work around is to open the source file first, then run the update script. The catch with that, is that you then need to do a Show All records on every source table in the older file so that you get all the records imported with your script.
Thanks to PhilModJunk!
It wasn't trivial, but I got 'er done!
Since there are actions performed on the file in an opening script, I had to set up a separate account and modify the opening script depending on the opening account. I use the new account when opening the copy file. The 're-login' script step was a key in the solution.
Annoying? Yes. Manageable? Yes