msi patch reprots success but fails update any files

Summary:
I’m applying a patch (myapp.msp) to an application. The patch works fine on XP.
On Vista, the patch works correctly if I right click on the msp file and select “apply.”
However, when invoked programmatically, with elevated privileges, the UI reports success but no files are updated. To make matters (much) worse, the application version number reported in "control panel"/"installed programs" is updated to the “new” version.
Detail:
Both the patch and the application were created with InstalledShiled Developer 8.0.
I’m applying the patch in 3 different ways: 1. Right click patch file and select “Apply” 2. With a batch file, invoked “as administrator”, containing “msiexec –p mypatch.msi” 3. From an application, with manifest that requires elevated privileges
From an end user point of view, all three methods result in the same sequence. Vista asks for approval for the elevation, then we walk through the Patch Wizard, and after some crunching it reports success.
However, only #1 updates the application correctly. #2 and #3 do not update any of the files, but they do update the application version number as appears in Control Panel / Installed Programs.
Examining the log files for method #1 vs. method #2 shows only one significant difference. The “pass” case shows MsiNetAssemblySupport= 2.0.50727.88. The “Fail” case shows MsiNetAssemblySupport= 2.0.50727.00.
Please advise how I can apply a patch programmatically.

Problem was caused by faulty patch. It is now resolved. Thank you!
"Trent" wrote:

Summary:
I’m applying a patch (myapp.msp) to an application. The patch works fine on XP.
On Vista, the patch works correctly if I right click on the msp file and select “apply.”
However, when invoked programmatically, with elevated privileges, the UI reports success but no files are updated. To make matters (much) worse, the application version number reported in "control panel"/"installed programs" is updated to the “new” version.
Detail:
Both the patch and the application were created with InstalledShiled Developer 8.0.
I’m applying the patch in 3 different ways: 1. Right click patch file and select “Apply” 2. With a batch file, invoked “as administrator”, containing “msiexec –p mypatch.msi” 3. From an application, with manifest that requires elevated privileges
From an end user point of view, all three methods result in the same sequence. Vista asks for approval for the elevation, then we walk through the Patch Wizard, and after some crunching it reports success.
However, only #1 updates the application correctly. #2 and #3 do not update any of the files, but they do update the application version number as appears in Control Panel / Installed Programs.
Examining the log files for method #1 vs. method #2 shows only one significant difference. The “pass” case shows MsiNetAssemblySupport= 2.0.50727.88. The “Fail” case shows MsiNetAssemblySupport= 2.0.50727.00.
Please advise how I can apply a patch programmatically.