What Windows versions it's failing under?

>The files are there - I can testify to that. When I run it manually, they're found, opened, converted - all under the same login as the one used for the scheduled task.
>
>And the task is set to run regardless of whether the user is logged in or not, and it errors the same both ways.
>
>BTW, this works without a problem in a couple of other places (with paranoid security settings) but with an older version of Windows.