From Blackberry Forums:
http://www.blackberry.com/knowledgec...83996&vernum=0
Problem
When the BlackBerry Enterprise Server rescans personal information management (PIM) items, the following Event ID 20539 may appear in the Application Log of the Event Viewer in Microsoft Windows® Administrative Tools:
The description for Event ID ( 20539 ) in Source ( BlackBerry Messaging Agent BESName Agent 1 ) cannot be found. The local computer may not have the necessary registry information or message DLL files to display messages from a remote computer. You may be able to use the /AUXSOURCE= flag to retrieve this description; see Help and Support for details. The following information is part of the event: {UserName@Domain.com} RescanPIMItems(3) failed: SUCCESS.
The following appears in the Debug logs:
[40856] (06/06 00:02:54):{0x274} {<username>@rim.net} Starting Memos rescan
[20539] (06/06 00:02:54):{0x274} {<username>@rim.net} RescanPIMItems(3) failed: SUCCESS
Note: There has been no impact on the user because of this issue.
Cause
No cause has been determined for this issue.
This is a previously reported issue that has been escalated internally to our development team. No resolution time frame is currently available.