Make sure you have a blank (will display as (Default) string key that is the name of the plugin as you want it to appear in decal. I don't think that would cause a failing issue, though. Perhaps try a single \ instead of your double?
Here are mine:
(Default) REG_SZ plugin game
Assembly REG_SZ dll name
Enabled REG_DWORD 1
Object REG_SZ Namespace.Class (e.g., RareTracker.PluginCore)
Order REG_SZ blah
Path REG_SZ path to Assembly
Surrogate REG_SZ {71A69713-6593-47EC-0002-0000000DECA1}
-----signature-----
We are like dwarfs sitting on the shoulders of giants. We see more and things that are more distant than they did,
not because our sight is superior or because we are taller than they, but because they raise us up and their
great stature adds to ours
