warning: Invalid argument supplied for foreach() in /modules/cck/nodereference.module on line 188

I created a new content type, and it uses a nodereference field. Now, when I go to create content for my new content type, I get the error:

warning: Invalid argument supplied for foreach() in /modules/cck/nodereference.module on line 188

but I am able to create the content without any problem.

This is with the latest CCK CVS and on beta4

cheers,
Ian