I used to like to customize my paths for various software, and have learned that (imho) it's best to just accept the software's defaults as much as is practical, because the more variables you introduce, the more bugs you are likely to uncover. Anyhoo, RXI is definitely installed as a VSI. I have the following path:
C:\Program Files\Cakewalk\Vstplugins\RXP\Contents\Loopmasters
But no "DnB Producer" under it.
There is a "DnB Producer" folder at "C:\Program Files\Cakewalk\Vstplugins\DropZone\Programs\05 - Grooves" and it has some similarly named .rx2 files, but not the one in question.
I'm not overly concerned about this. I have "bigger fish to fry" in understanding my new 21st century rig.
Pentagon is a cool looking synth. I am glad that's working and am looking forward to playing with it.
-Jeremy