Problem with installation

I am having problems with this plugin. When I install, I get this at the top of the page:

Warning: preg_match() [function.preg-match]: Unknown modifier ')' in /home/content/e/x/3/ex3031/html/betterworldprograms/wp-includes/class-wp.php on line 198

Warning: preg_match() [function.preg-match]: Unknown modifier ')' in /home/content/e/x/3/ex3031/html/betterworldprograms/wp-includes/class-wp.php on line 199

What should I do?