Locked out of admin page

I seem to be locked out of my admin/dashboard page. When I try to log in through /wp-admin I get this error and no way to bypass it:

Warning: Cannot modify header information – headers already sent by (output started at /home7/craftin5/public_html/wp-content/themes/StudioBlue/functions.php:48) in /home7/craftin5/public_html/wp-includes/pluggable.php on line 897

I had removed the problem code last night and my site is fine, but I can’t access the backend all morning due to the error message.

I need to resolve this ASAP – any tips out there?