Errors in rhevm log files

2013-01-11 20:17:43,423 WARN  [org.ovirt.engine.core.bll.UpdateVdsCommand] (pool-12-thread-38) CanDoAction of action UpdateVds failed. Reasons:VALIDATION.VDS.HOSTNAME.HOSTNAME_OR_IP
2013-01-11 20:17:43,423 ERROR [org.ovirt.engine.core.bll.RegisterVdsQuery] (http-0.0.0.0-8080-10) RegisterVdsQuery::HandleOldVdssWithSameHostName - could not update VDS ldssrvprojhv05.bjss.co.uk
2013-01-11 20:17:43,423 ERROR [org.ovirt.engine.core.bll.RegisterVdsQuery] (http-0.0.0.0-8080-10) RegisterVdsQuery::HandleOldVdssWithSameHostName - Fault - ENGINE
2013-01-11 20:17:43,423 ERROR [org.ovirt.engine.core.bll.RegisterVdsQuery] (http-0.0.0.0-8080-10) RegisterVdsQuery::HandleOldVdssWithSameHostName - CanDoAction Fault - VALIDATION.VDS.HOSTNAME.HOSTNAME_OR_IP
2013-01-11 20:17:43,429 ERROR [org.ovirt.engine.core.register.RegisterServlet] (http-0.0.0.0-8080-10) Failed to run RegisterVds.

Can anyone help and explain whats going on please ??