Thanks for posting the log.
It looks to me that the installer is failing while restarting one of your multiple IIS sites, after the install of IIRF has essentially succeeded. But, the failure to start one of the sites is treated as a general failure, and so the entire installation
is rolled back.
If I understand the problem correctly, you have multiple distinct sites that are configured to use the same port on the server. Not all of these sites are intended to run at the same time. But the IIRF installer is naive, and attempts to restart all sites.
Although I can't be certain this is the problem you are experiencing, this is clearly a bug in the IIRF installer.
I'll fix that in the installer, and post a new MSI to the workitem. I think what IIRF ought to do is restart the sites that previously had been running. For that it needs to keep track of which ones it had shut down at the beginning of
the installation procedure. This shouldn't be too difficult to do.
After I post the new MSI, if you could run the install again with that new MSI, I'd appreciate hearing your results.