I assume you mean 'why is kibs no good?' rather than 'why rob?', yes?
I'm not Bert, but I would guess that the answer is that the word 'kibs' doesn't mean anything to us, here in the US at least (for Bert and me), and it doesn't seem to have a meaning which is easily found via Google, or via resources like dictionary.com. Google does list several possible acronyms, but you did previously say that you were assuming that the previous suggested acronym was not allowed, so it would seem silly to suggest another acronym. So I guess the question is, what does 'kibs' mean to you? Is it a word of the English language? To me, the answer is no.
As an aside, I also agree with those who have previously suggested that proper nouns should not be allowed. Especially in an international context - people could make up any random string of letters, and say 'that's my Aunt's name'. Let's try to stick to things that are easier to agree upon. Like, say, can I find it in a reasonably well-known dictionary? Personally, I prefer dictionary.com and m-w.com - if only because access to the OED is not free for most people, especially outside the UK. Our loss.
Anyway, carry on, and have fun. [ November 04, 2008: Message edited by: Mike Simmons ]
Re-iterating Mike's earlier suggestion - try to change a different letter than the one the person before you changed, makes it more difficult than getting a list of all the words that rhyme with each other.
I am agree with Mike Simmons to the point of meaningfulness of our game. Steve Luke look i follow your suggestion, i think so! & Thanks Raghavan Muthu for giving me suggestion so read all rules & play further properly. Actually i am not previously played any word game rather than this javaranch meaningless Drivel. So i make mistake & now i think i found all rules of all word games on Wikipedia.