Core is actually a discontinued product that eventually was turned into Prose. There may not be a solution here in the forums.
You are welcome to contact one of the customizers in the drop down above (in the upper black bar on this page).
These forums were CLOSED to new posts on November 19th, 2012. New forums are here: http://www.studiopress.com/forums/
and you will need to SIGN UP AGAIN.
If you need assitance with setting up your theme, go to http://my.studiopress.com/
and read the SETUP links or the TUTORIALS link on the side tab.
If you need Account Assistance
, file a help desk ticket at the same location.