Warning: Invalid argument supplied for foreach() in element_children()

Hello,

I've noticed an error on pages of my site where I use field collections. Judging from what it says it actually seems unrelated to Field Collection, but like said, I only get the error on page where I use a field collection.

Warning: Invalid argument supplied for foreach() in element_children() (line 6244 of /var/aegir/platforms/dev/theaim-base_03/includes/common.inc).
Warning: Cannot use a scalar value as an array in drupal_render() (line 5723 of /var/aegir/platforms/dev/theaim-base_03/includes/common.inc).
Warning: Cannot use a scalar value as an array in drupal_render() (line 5778 of /var/aegir/platforms/dev/theaim-base_03/includes/common.inc).
Warning: Invalid argument supplied for foreach() in element_children() (line 6244 of /var/aegir/platforms/dev/theaim-base_03/includes/common.inc).
Warning: Cannot use a scalar value as an array in drupal_render() (line 5723 of /var/aegir/platforms/dev/theaim-base_03/includes/common.inc).
Warning: Cannot use a scalar value as an array in drupal_render() (line 5778 of /var/aegir/platforms/dev/theaim-base_03/includes/common.inc).

Has anyone else received this one? I've googled it and so far I've found a similar case in the issue list of the Form Builder module, but that's it. It doesn't actually stop the site from working, but I'd like to know what is causing the error.