You need to start eclipse using the iss_mcu_ide_eclipse-launcher.bat to configure the environment variables.
Looking at your other issue I presume this is now working for you also?
Yes. I didn't realize that opening the Eclipse.exe executable in the folder C:\IntelSWTools\ISSM_2016.0.027\eclipse did not load the proper configuration. I will use iss_mcu_ide_eclipse-launcher.bat in the future. Thanks!