If the DAT version shown in ePO is not the same as the DAT version on the client machine, then usually it means that the client machine has not been able to communicate the new information to the ePO server.
Before anything else, check the agent logs on the affected client machine and look for communication errors. There are a lot of articles in the knowledgebase to help you.
ok thank you for the reply. i will check once i am in the office. i just wonder why the affected client receiving an updated dat version coming from ePO. but the report generated states that the client is non-complaint.