The diagnostic message that appears is not always accurate. In order to know whether your keyword(s) is (are) in reality showing or not, is to use a proxy of the region targeted and search there for the keyword(s). Your keywords may be showing on top of the page and in diagnostic it may show "We only occasionally show your ads due to the budget you set" .... This is a strategy used by G to fool newbies, so that newbies will increase bids, increase budgets for G to suck the maximum out of a person, until the person has learnt about things.
many times when i see "We only occasionally show your ads due to the budget you set" and then I check using a proxy of my targeted regoin(s), my ad is in reality continuously showing at top of the page (where ads show on top). It is a learning curve and anytime you have questions, please do post them, as there are several GAds tenured members who have a good idea about GAds and who do guide people in a fairly correct manner.