Well you have to rule out the obvious.
A good place to get a handle on the most common reasons for not being able to see one's ad, is the AdWords Help Center. Here are a couple of links:
Why can't I see my ad?
[adwords.google.com...]
Other potentially useful info:
[adwords.google.com...]
AWA
Anyway, it's probably because of expanded matching [adwords.google.com] that it's happening.