There is a settings change you can make on your computer to make it pop up the failure message causing this.
In My Computer / Right Click and go to advanced settings.
Go to Environmental Variable.
set (the environment variable)
VSTO_SUPPRESSDISPLAYALERTS = 0
VSTO_LOGALERTS = 1
Visual Studio Tools for Office creates the log file in the folder that contains the application manifest
<Manifestname>.manifest.log
By default on a non-developer machine the VSTO runtime will not display loading errors. Setting this environment variable will help you determine the nature of failure.