A message like this suggests that details in the Windows Installer cache on the computer has got somewhat out of sync with itself through some actions that somebody (or some process) has done in the past.
I'm not sure that it will help you in any concrete way, but the following page talks about this situation: Missing Windows Installer cache requires a computer rebuild
If you know exactly what version of the FlexNet inventory agent was installed on this computer in the past then you could potentially download a copy of the MSI file for that agent version (available from the FlexNet Manager Suite web UI) and point to that file when prompted.
You may get some insight into what Windows Installer thinks is installed by executing a PowerShell command like the following:
Get-WmiObject -Class Win32_Product -Filter "Name LIKE 'FlexNet%'"
Be aware that executing this will cause Windows Installer to perform a consistency check on installed packages (as described here and here), and may in itself cause the error message you're seeing to pop up - so it may not give you any useful information; I'm not sure.
Failing the above, the msizap tool may help to force the removal of references in the Windows Installer cache to the FlexNet inventory agent package and allow the process you're trying to do to proceed. To use msizap you will need to work out what package code Windows Installer is thinking is installed - I'd be looking in the MSI log from the process you're trying to do to see if it gives any indication of the package code.
I hope some of those ideas get you at least one step further further!
(Did my reply solve the question? Click "ACCEPT AS SOLUTION" to help others find answers faster. Liked something? Click "KUDO". Anything expressed here is my own view and not necessarily that of my employer, Flexera.)
