To get this scenario working on the Steam version of Marathon Infinity...
1) Rename "Visions" to "Visions.imgA"
2a) Open "scripts/emr v2.0.mml" in your text editor of choice
2b) Edit line 96, so Visions is repointed to Visions.imgA.
2c) Save the file and close.
3) Select EMR from the Scenario menu when booting up Marathon Infinity and play.
P.S. Will this be headed to Steam Workshop soon?