It seems that all updates are now via the Cloud, or a "Cloud like" process, so these links may help
U44.. update error http://forums.adobe.com/thread/1289956 may help
-more U44.. discussion http://forums.adobe.com/thread/1275963
Please look at the following possible Premiere Elements 12 solution for the 12 to 12.1 Update.
I am assuming that you are using Windows 7, 8, or 8.1 64 bit. If others, please supply more details.
Do you have Premiere CC or any Creative Cloud products on this same computer?
Right click the Premiere Elements 12 desktop icon and select Run As Administrator. Also, assure that you are running your
computer and Premiere Elements from a User Account with Administrative Privileges.
Disable the antivirus and in particular the firewall(s).
Then open Premiere Elements 12 to Expert workspace Help Menu/Update and determine if you can Update from 12 to 12.1.