This usually happens when the macro security settings are set to High. Microsoft PowerPoint does not load the add-in and also does not show any message. You will need to turn the macro security settings to Medium.
After installing the add-in, you might want to turn the macro security settings back to High. It won't affect the already installed add-ins because of another option:
Also check this link to see if you are seeing this problem: PPT2002: PowerPoint Can't Load Add-in When You Lower the Macro Security Level. |