Hi Richei Creative,
These would be my suggestions:
Create a new user account with administrative rights, log out of your current account and into that one, launch Adobe Application Manager and attempt the Photoshop update again.
Instructions if you need them - http://support.apple.com/kb/PH11468
If this fails, uninstall Photoshop (Applications > Utilities > Adobe Installers) and reinstall Photoshop then from Adobe Application Manager the attempt the Photoshop update again, also from the newly created user account.
Hope these help,
-Dave