I installed Inventor 2014 User Tools. The install has no problem, but I don't have the tools in Inventor. In the Addin manager there is no User tools.
I tried to repair and reinstall, this is the same thing.
If the windows UAC is off, Antivirus Off and was installed "as administrator" at the default location: C:\Users\Public\Documents\Autodesk\Inventor 2014\SDK\... => normaly should work.
Here is a link to another post on the same subject..
I Hope that can help