I think Dave is again spot on.
Looking though your site from page to page they only change by 8 or so words. Then also linking the "home" back to holidayhomelistings.com/index.php
and not to http://www.holidayhomelistings.com you duplicated the entire site.
Results 1 - 1 of 1 linking to http://www.holidayhomelistings.com/index.php
I can see you
PR dropping from a 4 down to a 1 or 0 on the next go round as well.