one of 5 mu sites lost categories and it's menu

Hi

Using thesis 1.85 and have a multi site http://fmsreliability.com

After updating to 3.7 this week, 5 sites worked fine, one lost the menu and categories (/publishing ) the other sites have similar plugins and features that are still working.

any ideas on what this error message means - seen when trying to recreate the custom menu?

Warning: Invalid argument supplied for foreach() in /home/fmsreliab/domains/fmsreliability.com/public_html/wp-admin/includes/nav-menu.php on line 1225

Warning: Cannot modify header information - headers already sent by (output started at /home/fmsreliab/domains/fmsreliability.com/public_html/wp-admin/includes/nav-menu.php:1225) in /home/fmsreliab/domains/fmsreliability.com/public_html/wp-includes/pluggable.php on line 899

cheers,

Fred