Gietas

I had something similar. Not with LSPDFR, but another plugin. Which Antivirus are you using? I use(d) Norton 360. Sometimes, the temporary files that RPH creates in the temp folder are deleted by Norton. When that happens, the mod doesn't work. You can try the following: Go to your temp folder by typing %temp% into your search bar.
There should be a bunch of weird named files (I have around 1000 of these). Mine looks like this:

Delete them all. You can even delete the whole temp folder, but Windows will ask you to keep a few files because some of them might be used by drivers or other programs. Just do what Windows tells you to do.
Then start RPH again.
It does work for me that way, but since I don't know what causes this issue for you, I'm not sure.
Hope it works.