Most likely this is it, BetaChat. When you change anything about your ad, including the URL, it will come down from partner sites until reviewed/approved.
This means that your ad will be showing on Google alone, rather than Google plus potentially hundreds of other sites.
I'm guessing the ad has not been reviewed yet. After the ad is reviewed and approved, you'll probably see this number come up again.
This is just a guess, btw. It is next to impossible to troubleshoot in this forum, since none of us can see your account. I'd really suggest contacting AdWords support by using the 'Contact Us' link on each page of your account. The support folks can see your account in detail, and really get to the bottom of the issue.