It has been awhile since I last updated and currently I am at version 5.0.41. At first I thought maybe this was the issue because when I tried to install from full it just sets there and spins, so I uploaded the install package to the tmp folder and tried that and it immediately throws this warning:
Please enter a package folder.
Unable to find install package"
Thinking it was a permissions issue I checked the files and folders and they are all correct "644 - 755". I also double checked to make sure the tmp folder was listed properly in the config and it is. Then I thought maybe I had a corrupt download so I downloaded it again. No matter what I have tried the update fails with the above error or just sets there and spins. Nothing in the error log file about it either, its just like the site refuses to recognize the install package.
For grins I tried to install on a few different sites to see if it was this site or its configuration and in all cases it is the same issue.