Statistics Collection Agent log contains entries such as:
10/3/2006 12:52:13 PM CAgent::ProcessStatistics Informational 601 Collecting statistics information from database '\\SERVERNAME\QMMEX$SERVERNAME$\Mail Source Agent\emwstat.dat'.
10/3/2006 1:03:05 PM CAffectedServer::CImportStat::ImportItems InternalError 2001 Predecessor object was not set.
110/3/2006 1:03:05 PM CAffectedServer::CImportStat::ImportCollections Warning 2004 Hierarchy import was not completed. The rest of statistics data will be imported during the next session.
$SERVER$ : The system cannot find the file specified.
Sometimes this error occurs when the database file gets corrupted, in the above example it would be the file:
'\\SERVERNAME\QMMEX$SERVERNAME$\Mail Source Agent\emwstat.dat'.
First step would be to try and repair the database:
1) Stop the Mail Target Agent on the problem server.
2) Stop the Statistics Collection Agent.
3) Open the emwstat.dat file under '\\SERVERNAME\QMMEX$SERVERNAME$\Mail Source Agent\
using Microsoft Access.
4) Open the tables "Session" and "Workflow" and delete all rows from these tables.
5) Rename the old log file EMWSCA.log to eg. EMWSCA.log_old
6) Start the Statistics Collection Agent and verify there are no errors in the new log file.
7) If the Statistics Collection Agent is working properly, start the Mail Target Agents on the 'SERVERNAME'
If this does not help, or if one can afford to lose the old statistics data then corresponding agent can be reinstalled. The previous statistics data will be lost as new emwstat.dat file will be created upon new agent install, but the statistics for further synchronization should be gathered again.