Unknown Error

Please Help!
I’m getting this error when I do to try to manage my pages in the dashboard:

Warning: preg_match() [function.preg-match]: Compilation failed: nothing to repeat at offset 1 in /home/content/65/7708665/html/wordpress/wp-includes/class-wp.php on line 198

Warning: preg_match() [function.preg-match]: Compilation failed: nothing to repeat at offset 1 in /home/content/65/7708665/html/wordpress/wp-includes/class-wp.php on line 199

Everything was working fine, but I was trying to delete all of my pages and posts so I could start over again. It still says that there are 17 pages published and 6 in trash, but I can’t see any of them in the list. Let me know if you need any other information. Thanks for the help.