I'm having the same issue as TinyDancer. I followed what they did, uninstalled 7D2D: deleted all mods and folders including the launcher, installed everything from scratch: I put prefabs into 7D2D Prefabs folder (not overwritten) and made Mods folder in 7D2D in which I put Config folder (containing rwgmixer) and Modinfo XML. Launched a new game without errors to the rwg file, flew around the map, no new poi's.
I then when into 7D2D Data folder combined your Config folder with 7D2D which replaced rwgmixer, still no dice.
I usually use the Launcher to load the game and add other modlets. I have tried launching without the launcher and still no Stallionsden prefabs.
There was a yellow config issue in the error log and I fixed it, still didn't work.
Any suggestions?