FYI, for those doing LDAP searches on Exchange servers, there seems to be some preference in Exchange to disallow searches that aren't initial searches (i.e. only x* will work, not * or *x). I'd been going nuts trying to figure out why I kept getting errors doing * searches.
More info at:
http://www.microsoft.com/Exchange/en/55/help/documents/server/XOG16007.HTM