You cannot configure the filter settings in Microsoft Forefront Security for Exchange Server.
This issue occurs if the handle for the AntigenPMDLL.dll file is not closed on the Scanjobs.fdb file in a timely manner.
To resolve this issue, install Microsoft Forefront Security
for Exchange Server with Service Pack 2 (SP2).
For more information, click the following article number to view the article in the Microsoft Knowledge Base:
Description of Forefront Security for Exchange Server with Service Pack 2
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.