On any policy where I enter a policy Requirement for Windows Operating System = 5.1 (XP) the device fails to grab the policy. The agent says the policy is "Non-Effective" and this error appears in it's log:

[ERROR] [08/18/2009 09:14:05.765] [1564] [ZenworksWindowsService] [62] [T5335] [Requirements Module] [SYSREQ.ExceptionInHandler] [The handler WindowsOsRequirementHandler threw an exception. System.InvalidOperationException: There is an error in the XML document. ---> System.InvalidOperationException: <WindowsOSReq xmlns='http://www.novell.com/ZENworks/Reqs/v1.0'> was not expected.
at Microsoft.Xml.Serialization.GeneratedAssembly.XmlS erializationReader1.Read149_WindowsOSReq()
--- End of inner exception stack trace ---
at System.Xml.Serialization.XmlSerializer.Deserialize (XmlReader xmlReader, String encodingStyle, XmlDeserializationEvents events)
at System.Xml.Serialization.XmlSerializer.Deserialize (XmlReader xmlReader)
at Novell.Zenworks.Zmd.XmlUtil.DeSerializeXML(Object xmlData, Type type, XmlSerializer xml)
at Novell.Zenworks.Zmd.XmlUtil.DeSerializeXML(Object xmlData, Type type)
at Novell.Zenworks.Zmd.XmlUtil.DeSerializeXML(Object xmlData, Type type, String rootElementName, String rootNamespace)
at Novell.Zenworks.Requirements.BaseRequirementHandle r.ProcessRequirement(Session session, Req req, Boolean inUserSpace)
at Novell.Zenworks.Requirements.Requirements.ProcessR equirements(Session session, GroupReq reqs)] [] []

If I remove the Requirement from the policy, it appears to successfully apply to the devices.

I didn't change anything overnight, what could have happened?