If you're running Windows 7 or Vista and you have UAC enabled, don't upgrade to PowerChute Personal Edition 3.0. APC doesn't know how to properly program for Windows 7 and Vista. Their system tray application needs administrative rights, and so a UAC prompt will appear after every bootup or login. APC knows about this issue, and they suggest reducing your security settings as a workaround.
Administrative rights are requested by the executable's manifest. The manifest could be edited or even removed. However, that would probably cause problems. Just use an older version of PowerChute Personal Edition; it works fine.