I have a simlilar problem, but for me, 9.1 hangs when I try to open any document at all. In other words, I can't get Reader 9.1. to work at all since I downloaded it. I tried uninstalling and reinstalling it with no improvement. Any help at all in resolving this problem would be appreciated. BTW, I have Vista Homw Premium.
I had the same problem and struggled with it also.
I finally solved my problem by uninstalling reader 9.1, air, acrobat.com and THEN after a restart, installing a lite version of reader 9.1 from this site: