I havefive pcs with linux red hat 9 platform to be synchronised

I m constantly getting this error msg when i try to use ntpdate

NTP: ntpdate: Server dropped: strata too high

I have made one machine as server,all the machines are able to ping each other.
But their clocks are not synchronised.

I have gone through many available solutions to this problem,but they could not find solve my problem.
Kindly Guide me.