Planet13 - 4:08 pm on Aug 10, 2011 (gmt 0)
I had this problem when I was trying to rank a page called widget-photos.html for the keyword widget photos, but it wouldn't rank at all. Instead, widget-images.html ranked for the keyword widget photos.
It turns out I had accidentally metta noindexed my HOMEPAGE and for some reason the effect was that the widget-photos.html page did not rank anywhere.
So check to see that your code and structure are ok, and that you don't have broken links or canonical problems or anything like that.