When VoiceAttack can't find a plugin referenced by the "Execute an External Plugin Function" action, it not only replaces the description with "UNABLE TO ACCESS PLUGIN - PLUGIN NOT AVAILABLE", but it also discards and does not display any data in the dialog window to set up said action.
I had to go into the .vap file, find the GUID for the plugin, and compile my own dummy plugin which returns that GUID, to make sure everything was set as I expected it to be. I feel this is less than ideal