I can see the problem ... you have named your custom folder "User Runtimes" which is confusing Poser.  External runtimes can't have the word "Runtime" or "Runtimes" in the name or Poser will default back to its native Runtime.  

Rename the folder to something you'll recognize (like "My Stuff") without the word "Runtimes" and then change the name in the prefs file and you should be ok.

Hugz from Phoenix, USA

Victoria

Remember, sometimes the dragon wins. Correction: MOST times.