The only Metis.exe I know to exist is the installer of the RoboMx combined with the Metis in the version written for that version of RoboMx.
Some Metis scripts don't work in all versions of Metis and not all versions of Metis work in all versions of RoboMx.
This is the reason why Bender always has bundled Metis with the RoboMx it was developped for.