Regarding the Okapi, the first time I played I examined the Okapi and he asked me a question. I thought it was a rhetorical question, meaning it wasn't expecting an answer. I examined the graveyard and got a response that sort of made sense, but I didn't realise it was actually telling me that my answer was wrong. I went round and round in circles for a little while trying to answer the question. Even when I knew the answer, I couldn't get it to accept the answer because I hadn't re-examined the Okapi. If it was me, I would do it something like this:
Talk to the Okapi and he asks you the question. Answer the question by just giving the answer (as though it was a verb) or using SAY <answer>. If the answer is wrong when you haven't used a verb, it will just give the normal "Not understood." response. If you use SAY and the answer is wrong, give the response you're giving now. If the answer is right, do what you do now when the answer is right. You can optionally set a flag when you initially talk to the Okapi so that you know he's asked you the question. For an example of this, see the handling of the magic word in my first Adventuron game, 'Seeker of Magic'.
Regarding the fishing rod, yes, I did try it, but maybe I didn't find the right verb. I'll try again. Thanks.