I googled for that issue and found out... and old post of mine .
In my case, I couldn't start IWP in FMP12 after installing FMP13, that updated Java to a newer version. Java version is still an issue with FMP and FMS.
Thing is FMP12 needs a specific version of Java because it was tested with it. Try to find Java version needed for FMP12, and check if the installed version is newer. If that's the case, I am pretty sure that's the cause of the issue. Interestingly enough, you may have more than one version of Java installed on a computer, but can't tell if that could break something else. This is very tricky. One other thing you may try is uninstall the actual version and install the one FMP12 is confortable with.
Hope that helps
Did you check the port 80 is not used before running FMP12?
Open command prompt then
netstat -an -p tcp
Opened the ports and it is working now. Thank you!