KB ID 0000530
Seen when trying to execute an eseutil command on an Exchange database:
Callback DLL not found
Unable to find the callback library jcb.dll (or one of its dependencies).
Copy in the file and hit OK to retry or hit Cancel to abort.
1. Download this zip file, and extract the jcb.dll to the “bin” directory on your Exchange server, then click OK to continue and eseutil will complete.
Email form Brian Jamurath
I ran into this recently on an Exchange 2003 server I was migrating. MS have released an updated ESEUTIL for 2003 to resolve http://support.microsoft.com/kb/946111