Two possible causes:
1) The printer name specified in OrPrinter is wrong
(this is less of a problem now that OrPrinter collects the printer names rather than requiring you to type them in as it origibally did).
2. There is nothing to print because Ór is not configured with the "Activate" option checked in the Live Results tab of the Competition dialog.
When the "Activate" option is checked, Ór creates a file with th results data in it, even if there is no internet connection. This file is what the OrPrinter program uses to print results from.