Thesis Theme css.php file error

I uploaded Thesis Theme and am getting the following error messages at the top of my WordPress Dashboard, any help? Where can I get a replacement file?

Warning: Invalid argument supplied for foreach() in /home/content/87/8880487/html/wp-content/themes/thesis_18/lib/classes/css.php on line 60

Warning: Invalid argument supplied for foreach() in /home/content/87/8880487/html/wp-content/themes/thesis_18/lib/classes/css.php on line 60

Warning: Cannot modify header information – headers already sent by (output started at /home/content/87/8880487/html/wp-content/themes/thesis_18/lib/classes/css.php:60) in /home/content/87/8880487/html/wp-includes/functions.php on line 861

Warning: Cannot modify header information – headers already sent by (output started at /home/content/87/8880487/html/wp-content/themes/thesis_18/lib/classes/css.php:60) in /home/content/87/8880487/html/wp-includes/functions.php on line 862