Weblogic Exception

Our application is deployed in weblogic 7.0. It is a simple deployment , no clustering or no load balancer.
But i recieved below exception in my server log at which point my response time was very slow:
<Error> <Management> <myDomainServer> <ExecuteThread: '1' for queue: '__weblogic_admin_html_queue'> <kernel identity> <> <141051> <Operation failed with message: Could not get logs from server 'myDomainServer' via Node Manager - reason: 'Target machine configuration not found'. This feature is applicable only to servers that were started up through the Node Manager.

I have never configured node manager for my application. nd when i recieved this error message, my application was active. And after this message i didnt do anything , byut my application started working fine. Only when this mesasge was thrown at that time the response time was slow and i got 500 internal server error in my appln screen.

If anyone hascome across any such issues please throw some light.

Thanks
Vishy>

I hope nodemanager service or daemon is running and possibly the servers were started.
Would you be able to replicate the same so that we will have clear understanding?