I installed the 3.1 patch file successfully yesterday. Like Ruth M. I did not "read the directions" for installing, but did read about the problems people were having.
As I recall, when I ran the puft3ua.exe file (for my 3.0 upgrade version) a window opened for my UFT 2.8 on my D drive and I had to go find the 3.0 on my C drive. Then I located the uftree.exe file in that directory and clicked (double-clicked?) on it and the patch installed. It happened so quickly that I had to open UFT 3 to verify that Help read "3.1 patch".
I read the directions this morning and I don't think they say to click on the uftree.exe file as the final step for installing.