Need help understanding Adwords Traffic Estimator data

I have entered the maximum value for CPC as $100, the maximum that is allowed by adwords. For some of my keywords, estimated daily clicks is zero. but however, local monthly searches, estimated avg. CPC, and estimated daily costs are not zero. Some of the keywords with estimated daily clicks of zero has quite high values for the other parameters. Could you please explain what this data implies? Should I remove this words from my campaign? Also, I don't know how much max daily budget to set. I want to set it at $20, but that results in very few estimated daily clicks. Thank you in advance.