[Zope] Error Type: error / 23 - 'too many files open in system'

Error Type: error Error Value: (23, 'Too many open files in system') This error appears on a page being rendered when it and another zclass are simultaneously being edited. This is strange and I dont see the relation. Where can I find docs on errors to research this? anyone seen this before? I thought Zope didnt care if a page was being modified...it renders the most currently saved version, right? Thanks, Trevor