Failed to log on to Microsoft Windows.

Hi,

I have Backup Exec 2010 installed on Windows Server 2003 R2 Enterprise, i received the following error sometimes:

"The job failed with the following error: Failed to log on to Microsoft Windows.

Ensure that your logon credentials are correctly entered and that they meet the following minimum requirements to log on to a Windows computer:

   - The credentials used are a member of the Backup Operators group.

   - For Windows Vista/2008 and later, the credentials have the Log on as a batch job privilege.

Additional privileges may be required to access resources on the Windows computer."

Are there any solution to solve this error completely? the credential user is a part of Domain Admin and a member of backup operaters.