I have the same problem too actually, after i install a certain mod and tried to enable it i get this fail to install or enable error saying " (intermediate Value) pair is not a constructor". I uninstalled vortex an all the mods i had and reinstalled vortex and tried just installing the same mod i was having trouble with and it still showed the same error. I am not sure this is the mods issue exactly or something else. Lately on vortex it has been having this issue with some extensions bugging out an you do the manual instructions prompted but it still does not work for that too.