Exchange Server

Hello,
Our exchange server is running Windows 2000 Server with Exchange Server 5.5 and I am trying to create a new public folder for our users, however, when I go to add a new information store I get the following error: ‘An internal processing error has occured : there is a problem with the information store. Try restarting the administrator program or the Microsoft Exchange Server computer or both. Microsoft Exchange administrator ID no:c1030743’
Can you please tell me what this error means and the fix? I have already rebooted the server to no avail, many thanks