error code #16820 - acrobat.com mandatory update available download will not install from version 126.96.36.199 to 188.8.131.52. When I try to download the update it fails with error code 16820. I can't install the update. Is there anyway to force the update to install. This occurs when I use IE9 64 bit. I do not get this error with IE9 32 bit or chrome. O/S is Windows 7 Ultimate. Original install date is 2010.