tangor - 10:35 am on Dec 12, 2011 (gmt 0)
Okay. Plan B... you have nothing to lose. Change URI (redirect that filename old to new, get new indexed), change "title" in head, and any H1 as well. Jazz those signals up, be a tad outrageous, leaving the rest of the content alone. Check back three months from now and let us know how that worked.
Serious suggestion. Sometimes the URI, "title" and H1 is the strongest signal. This method worked 4 out of 6 problematic pages for me.