PS I think I figured it out. I had something similar today in a new blog: http://allthatpetcare.com/ I just loaded the cform plugin from the same site as on my other blog a couple of days ago.When I deactivated cforms the error message went away. So I guess it has something to do with that.
Warning: Unknown: open(/home/users/web/b2632/moo.leah/cgi-bin/tmp/sess_84d2945252da5a268b2fbf973aeae9d6, O_RDWR) failed: No such file or directory (2) in Unknown on line 0
Warning: Unknown: Failed to write session data (files). Please verify that the current setting of session.save_path is correct (/home/users/web/b2632/moo.leah/cgi-bin/tmp) in Unknown on line 0