You may get this error in the Output Processer if you do not have any printers selected in Settings\User Preferences.
Go to Settings\User Preferences and select a printer for each output type. Click OK and try to process output again and it should now work with out an error.
Please reach out if any further assistance is required.
Helpdesk: 866.237.2878
Email Support: helpdesk@alpineitw.com