It is possible that you have a bad PEC.
You don't actually have to use Unified Messaging for Outlook 2010.
Here is a workaround.
Note: CallPilot v4 or v5 Desktop Messaging client does NOT need to be installed; regardless, if you attempt this you'll receive the error "Either there is no default mail client or the current mail client cannot fulfill the messaging request. Please run Microsoft Outlook and set it as the default mail client." which you can safely ignore; Outlook likely IS set as the default mail client already. I uninstalled mine completely.
Open Outlook and select File>Account Settings (or access the Outlook Mail Profiles via the Control Panel>User Accounts>Mail or change the Control Panel "View by:" option to "Large icons" or "Small icons" and select "Mail")
Within the "E-mail" tab, click "New", select "Manually configure server settings or additional server types", click 'Next"
In the "Add New Account">"Choose Service" window, select "Internet E-mail"; click "Next"
In the "Add New Account">"Internet E-mail Settings" window, Enter "Your Name:", an "E-mail Address" in a valid format, change the "Account Type:" to "IMAP", enter your Callpilot IP or DNS address in the "Incoming mail server", enter your organizations' existing SMTP server's IP/DNS address in the "Outgoing mail server (SMTP):" block; enter your voice-mail box extension in "User Name:" (e.g. 101) and your voice-mail box password under "Password:" (e.g. 1111); leave the "Require logon using SPA" box unchecked
Click "Next" to test the settings; or click "More Settings" to make some refinements, primarily which would be under the "General" tab on the "Mail Account" block; change the name here to better title the resulting .pst file that will be created.
After this, you're done and pretty much back to what you had under Outlook 2007 and before.
-SD-