fbdc | Facebook Disconnect is a browser extension | Browser Plugin library

I won't work with a (temporary) file, just do it all in memory.
The "usual" way to get a command's output into a variable is a for /f loop.
Togheter with find and proper tokens and delimiters, you can quite precisely choose a proper substring.

I expanded it a bit to work also with multiple Network adapters, Dimms and Disks.

The most likely issue is the message in the log:

Disallowing installation of component: {CCBFECA9-31FE-4D5C-A31A-5A264F69FD58} since the same component with higher versioned keyfile exists

This implies that you did not update the file version of that Dll. The result is that the Dll is missing and your app crashes. There's a good explanation here:

https://blogs.msdn.microsoft.com/astebner/2015/11/16/why-windows-installer-removes-files-during-a-major-upgrade-if-they-go-backwards-in-version-numbers/

The basic issue is that early in the install it decides that it won't overwrite that file because the existing version on the system is greater than the "new" incoming file, so it decides not to install it at all. Those are the file version overwrite rules. However, later on the upgrade occurs that removes all the old files, but it still erroneously sticks with the idea that it shouldn't install that file, so it's missing at the end of the install.