Install problem because "install file is damaged"

Question

My client is periodically getting the following error on some of their identically configured Win7 machines:
"Sorry, an error has occurred.  The application could not be installed because the installer file is damaged.  Try obtaining a new installer file from the application author."
I am the application author.
Here is the install log from a problematic machine:
[2013-01-03:09:50:33] Application Installer begin with version 3.5.0.880 on Windows 7 x86
[2013-01-03:09:50:33] Commandline is: C:\Rate_Calculator\XXX_Air_Files\calc-xxx-rate_0_6_2.air
[2013-01-03:09:50:33] Installed runtime (3.5.0.880) located at c:\Program Files\Common Files\Adobe AIR
[2013-01-03:09:50:34] Unpackaging file:///C:/Rate_Calculator/XXX_Air_Files/calc-xxx-rate_0_6_2.air to C:\Users\xxxxxx\AppData\Local\Temp\fla3A80.tmp
[2013-01-03:09:50:34] Application signature verified
[2013-01-03:09:50:34] Unpackaging/validation complete
[2013-01-03:09:50:34] No app located for appID 'com.tappsolutions.calc-xxx-rate' and pubID ''
[2013-01-03:09:50:36] Converting unpackaged application to a native installation package in C:\Users\xxxxxx\AppData\Local\Temp\fla452B.tmp
[2013-01-03:09:50:37] Native installation package creation failed: [ErrorEvent type="error" bubbles=false cancelable=false eventPhase=2 text="Unhandled exception Error: open[110]: MSI Error" errorID=0]
Here is what I have done:
1) I searched the fourm and found this report with no solution: http://forums.adobe.com/thread/801670
2) I had the client send back the install file and I did a compare with an install file that was successfully installed on my machine; They are identical.
3) The client can specify a different install location to successfully install.
4) Client confirms that they did not install previous installs under a different user or administrator.
5) This problem does not happen on all machines; we do not know what the difference is between the problematic machines and non-problematic machines.
6) The problem began when I delivered 0.6.2 of my app, on the problematic machines they can go back to 0.6.1 and successfully install.
7) I unjared the 0.6.1 and 0.6.2 .air files and compared them.  Nothing unusual was found.
8) The problem went away when I delivered 0.6.3, but reappeared when I delivered 0.6.9.

Answer 1

Hi Michael,
Does it make any difference if the user uninstalls the previous version and then installs the latest? 
Googling MSI error 110 seems to indicate that this is an open/locked file issue.  Is the app running when they attempt to update?  Do they happen to have their drive/folder encrypted or compressed?
It might help to enable MSI logging and take a look at what it spits out.  Instructions for turning this on and locating it can be found here.
Thanks,
Chris