Hostname change server not working

Hi,

I have done a fresh installation of WAS 6.40 and EP7.0.and Its working fine.

I chnaged the hostname according to the steps given in SAP Note 757692 .

The host name has been changed but the server works only for 30 mins and then i need to restart it.

Without changing the host name the server works fine..

Any Pointer??

Regards

Indu Garg