It may have been a pre-Gates (or Omens). I couldn't get it to work either. I clicked on the rock and it said Perhaps if you had a reason to go in there your could. Or something like that. Guess it is closed now.
You could try actually interacting with the NPC instead of asking for someone else to tell you what keyword(s) to use. If you hail him and follow the prompts, like most EQ quests, you will get a mission/task/quest/reward. The "prompts" are usually words or phrases enclosed in [brackets] . Oy....