'An administrator' causing Air to be refused is not an isolated problem! The issue repeats itself all over the werb in various forms. In my case the thing won't instal on an XP Home SP3 system, though it did perfectly easily 7or 8 months' ago (I had to uninstal it, but have yet to succeed in putting it back). My failure occurs within less than one second of the installation attempt being made (as recorded by msiexec.exe). Unfortnately, Adobe's direct help system merely repeated various mantras (run Windows Instal Clean Up Utility, etc. etc.) when I asked them about it at length a number of months' ago. Annoyed that this is the only application I cannot get onto my system, I had another go, on my own, today. Nix! Maybe Adobe have deliberately fixed it so that it only works on one or two selected systems, to force people away from old things like XP? As can be seen, one is reduced to finding sinister reasons for the failure.