Symptoms:
During installation, an error occurs and says: "Error 1316. A network file error occurred while attempting to read from the file C:\Users\...".  The filename at the end of the message may differ for each user and each add-in.

Cause: 
An older version of the add-in is still installed.

Resolution:
We create the installers to automatically uninstall any previous versions.  However, the uninstall of the previous version sometimes fails for unknown reasons.  When that happens, this error occurs.  To fix it, manually uninstall the add-in by exiting out of the current install (if it is still going), then go to Control Panel…Programs and Features.  Find Sperry Software in the list, then select Remove.  After the removal, run the installer again.    If the installer fails again, then exit the installer, then download and run the Uninstall Add-Ins tool found on http://www.SperrySoftware.com/Outlook/Tools.asp. After it completes, run the installer.