IE 7/8 - theme does not display for logged in users.

Excellent theme, works like a dream except for one glitch/conflict. When I log in as an authenticated user (my default admin account) using Internet Explorer 7 or 8, the theme does not function at all. It's fine on Safari, Firefox and Chrome. I inserted the MS code to make it IE7 compatible, but while that apparently did clear up an annoying "array_merge(): Argument #2 is not an array" error message, the theme still does not function when I log in. It is fine if I view as an anonomous user.
I have attached a screen grab.