fathom - 8:37 pm on Jan 29, 2012 (gmt 0)

There doesn't need to be anything wrong.

In retrospect, the only reason a homepage "ranks" (in most instances) is because that is the page that acquires the most links.

If for example your sub pages starts getting direct links and the link on the sub-page to the homepage says "HOME" short of your website being "HOME" related (like home furnishings, home repair, home business) the rankable page for most other phrases is less likely going to be the homepage.