Poser Pro 2012 would install to program files; the content should be installed to the default location in public documents.

There will still be a modest runtime in the Poser Pro 2012 folder, but it just has things needed by Poser itself. Do not put your own stuff in that program files runtime. It wasn't having Poser in program files which caused your problems; it was your attempt to install content to the program files runtime (which was blocked by User Account Control) which caused the problem.

Your homebuilt and purchased content should go to either the downloads\runtime within public documents, or to a runtime on a secondary hard drive.
Install the morphs++ and elite packs to the same downloads\runtime in which you install the target dolls.

Install the SR updates; SR 3.1 fixed several bugs and added some nice features. I can't recall offhand if that was the last update. I have Poser Pro 2012 (with all SR updates) on a 64bit Win7Ultimate machine, Program goes in program files, content into public documents. Just let the installers choose their own default locations and you'll be alright.

Poser 12, in feet.  

OSes:  Win7Prox64, Win7Ultx64

Silo Pro 2.5.6 64bit, Vue Infinite 2014.7, Genetica 4.0 Studio, UV Mapper Pro, UV Layout Pro, PhotoImpact X3, GIF Animator 5