Enterprise Manager

If I verify the dataguard configuration within the EM (Additional Administration -> Verify Configuration), the check of the agents of the primary and the standby database results in a warning, that something could not be written to a process and that as result a switchover could fail. What does this warning mean ?

I have found something in an oracle book that during the check of the agents an SQL*Plus job is generated if credentials are available or a ping is generated instead, if the creadentials are not available.

Is this verification logged in any file to analyse in details why this check fails or has anyone an idea what is wrong in the configuration?