SAP-XI, permission of the instance.properties file changes unexpectedly

Hi forum,

I have XI installed in HP-UX,

the permission of the instance.properties file (/usr/sap/<SID>/<instance name>/j2ee/cluster/instance.properties) in my XI system (installed in HP-UX), changes automatically, and hence the server starts giving problem like, JCO error while message-mapping, etc,

can u tell me how the permission changes on the fly,

I mean to say, in proper condition we keep it as rw_rw_rw, but it changes to rw_ ___ ___,

pls help,