Nobody knows why then? Wow, support here sucks.
Yes, support is terrible. I´ve seen many people with the same problem and have not been able to find an answer anywhere. It seems to be a common problem and Adobe has not provided a solution to this problem. At least nowhere that I can find it. Hopefully someday we will get a solution.
Make sure everything is closed on you computer. Before trying to reinstall turn on Hidden Files and Folders. Go to C:\Documents and Settings\USERNAME\Application Data\Adobe\ and delete the AIR folder. Then clear your Temp files from C:\Documents and Settings\USERNAME\Local Settings\Temp. Empty your trash can. Try reinstall.
Which is odd, I've attached the log file and everything.
Adobe air is BROKEN.