Although the fix is to create a filter to basically ignore the message, in this instance it cannot be done on the local Blackberry handset and must be done from inside the Blackberry Enterprise Server (BES) console.
Open the Blackberry Administration Service and click Manage Users from the main landing page. Use the Display Name search field to locate the user experiencing the problem. Click on the user from list of returned results.
Click Edit User.
Click Default Configuration.
Click on the E-mail tab.
Name the filter descriptively, and tick Body: and insert the string "Outlook Message Manager", and ensure Recipient Type is selected and Sent directly to me. You must also tick Do not forward e-mail messages to the device.
Use the + icon to save the configuration. The user will no longer get the annoying message.