Why is setting Addins("FileName").Installed = True failing with VBA?

I'm trying to programmatically install my addins so with a click of the button the program can be updated for my coworkers. I uninstall and remove the old add-in then copy the most up-to-date addin from our server using the Add method and setting the Copy argument to True. I can get the Sub to work on my computer and another co-worker's computer but another one of my coworkers I can't get it to work at all. It gets to the .Installed = True line and states something to the affects of it can't set Install to True. I've tried attacking the problem from a bunch of angles and am at whits end. I've made sure that I added the add-in to the list of addins. It does show up in the list. I've tried referencing it as an Add-In object by looping through the Addins even and searching for the one where it's name is that name then using the Addin object. I've tried combining the Add method and Install method in the same line. I've tried reconfiguring the security settings to enable all macros and trust the vba project. I digitally signed the project. I put the file in a trusted location. Even set it to be OK to trust server locations and still no go. I also tried adding it then opening the file then setting Installed to True. None of that works. Has anyone else encountered this. I've looked all across the web and can't seem to find an answer. And all of these methods worked on my computer and another coworkers but not this one computer. He has the same version of windows and all, I tried copying every setting I could think of.

I'm thinking it has to be something with the security settings somehow. Would greatly appreciate if someone figures this out.

Thanks!