Steinberg Plugins don't work anymore...help

i found another way to explain the problem and maybe replicate it
i’m on windows7 64 bit with Nuendo 5.5.2 both 32 or 64 bit

if i trash my entire AppData-Roaming Nuendo folder (to rebuild it from scratch the first time i open nuendo again) everything works and plugins are recognized…
now i go to “plugin information” so i can add another path where i keep all my other plugins (kontakt absynth etc etc)
after restarting nuendo sees my newly added plugins but original STEINBERG plugs DON’T WORK ANYMORE…i can see them but if i click on them nothing happens

the same plugins i add are in the same folder with the same path that i also use with cubase 6.5.1 and things work perfectly there.

i also tried uninstalling and reinstalling nuendo but it didn’t work

it must be a bug and i’m getting completely frustrated, it’s been almost a month and nuendo has become unusable for me.

i hope you can understand my frustration

best
-mike