My customer just changed from Groupwise email to outlook. How can we change Rio to use outlook instead of Groupwise email?

Here is the email;

We've recently switched from Groupwise to Outlook, but when a user wants to send a Laserfiche document via email it is still trying to open Groupwise.  How can we default this application to send through Outlook?  I've uninstalled my Groupwise and tried it again, the Windows Messaging Service window comes up but it's asking me for the location of the Outlook Post Office.