cannot login after changing hosts

[WFPaul]

We moved our get simple websites from one host to another. Everything on teh websites themselves appears to be working, but we can no longer log into the admin panel, using admin nor any other user. During login attempts something flashes briefly before returning to the login screen. When I set the site for no login, I can see this at the top of any admin page:

Warning: Cannot modify header information - headers already sent by (output started at /home/fnpschap/public_html/pawpaw/admin/inc/template_functions.php:2591) in /home/fnpschap/public_html/pawpaw/admin/inc/cookie_functions.php on line 23

Warning: Cannot modify header information - headers already sent by (output started at /home/fnpschap/public_html/pawpaw/admin/inc/template_functions.php:2591) in /home/fnpschap/public_html/pawpaw/admin/inc/cookie_functions.php on line 24

Any ideas?

Paul