Can you check your php.ini file and see what the settings are for "display_errors" and "error_reporting"?
Try setting display_errors to Off and see if it helps. If it does, then consider lowering your error_reporting level for your production site, such as setting error_reporting to E_ERROR. Be sure to restart apache or IIS after you've changed that though.
I think germi is right in pointing out it's runtime warnings that's being displayed not fatal errors.
If the warnings go away, you should be able to re-enable bookmark function afterwards. Finger-crossed
