sitemaps array error being generated

i have a nine site MU and whenever i turn on sitemaps i get the following error:
Warning: in_array() [function.in-array]: Wrong datatype for second argument in E:\wamp\www\foambook\wp-content\plugins\wordpress-seo\inc\class-sitemaps.php on line 560

i could live with that, except that i cannot use the quickedit function for posts or comments, which is a drag, and i also get the error when i try to add a tag.

prior to upgrading to version 1 today i was able to turn off the sitemaps on the subdomains, now i can only switch the function on or off for the whole site.