The newbie is stuck!! Coding mistake.

Was trying to input my meta keywords and description. Found i placed it in the wrong area. Then replaced the copied/original code for template function.php, saved changes then got this message. Of course i cant get into the dashboard now. Can i get some help please?

Warning: session_start() [function.session-start]: Cannot send session cookie – headers already sent by (output started at /home/mph67/public_html/abspreservation.co.uk/wp-content/themes/FlexxUncorked/functions.php:124) in /home/mph67/public_html/abspreservation.co.uk/wp-content/plugins/si-contact-form/si-contact-form.php on line 846

Warning: session_start() [function.session-start]: Cannot send session cache limiter – headers already sent (output started at /home/mph67/public_html/abspreservation.co.uk/wp-content/themes/FlexxUncorked/functions.php:124) in /home/mph67/public_html/abspreservation.co.uk/wp-content/plugins/si-contact-form/si-contact-form.php on line 846

Warning: Cannot modify header information – headers already sent by (output started at /home/mph67/public_html/abspreservation.co.uk/wp-content/themes/FlexxUncorked/functions.php:124) in /home/mph67/public_html/abspreservation.co.uk/wp-includes/pluggable.php on line 868