This problem occurs because of there is not enough thread safety around the configuration objects.
To resolve this problem, obtain the latest service pack for Microsoft Exchange 2000 Server. For additional information, click the following article number to view the article in theMicrosoft Knowledge Base:
301378 XGEN: How to Obtain the Latest Exchange 2000 Server Service Pack
The English version of this fix should have the following file attributes or later:
Component: Post Office Protocol version 3 (POP3)
NOTE: Because of file dependencies, this update requires Microsoft Exchange 2000 Server Service Pack 2.
Microsoft has confirmed that this is a problem in Microsoft Exchange 2000 Server. This problem was first corrected in Microsoft Exchange 2000 Server Service Pack 3.