Awesome- turns out, Windows 8 users need to do the following:
1. Disable UAC through the registry (run regedit.exe):
Location: HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Policies\System
Key: EbableLUA
Value data: 0
2. Unblock all the files in the download: In unzipped folder, select all, right-click for properties, and choose Unblock.
3. Run setup as Admin
4. Reboot
5. Run as premise Builder as Admin
Doing the above got my Premise working- thank you for your help!