So i'm trying to look at this as logically as possible.

Warning: session_start() [function.session-start]: Cannot send session cache limiter - headers already sent (output started at /mnt/gs01/herd04/8190/domains/modern-contemporaryfurniture.com/html/includes/configure.php:135) in /mnt/gs01/herd04/8190/domains/modern-contemporaryfurniture.com/html/includes/functions/sessions.php on line 108

Warning: Cannot modify header information - headers already sent by (output started at /mnt/gs01/herd04/8190/domains/modern-contemporaryfurniture.com/html/includes/configure.php:135) in /mnt/gs01/herd04/8190/domains/modern-contemporaryfurniture.com/html/includes/init_includes/init_templates.php on line 78
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Warning: I am able to write to the configuration file: /home/8190/domains/modern-contemporaryfurniture.com/html/includes/configure.php. This is a potential security risk - please set the right user permissions on this file (read-only, CHMOD 644 or 444 are typical). You may need to use your webhost control panel/file-manager to change the permissions effectively. Contact your webhost for assistance.
The warning is talking about headers being sent out. Well, the problem with every call to a css file is 403 forbidden and they are all located in the head of the document. So is the logo and it is not accessible. But the favicon.ico is located in the head and it still shows up.

Let us all ponder.