Message Tracking Task does not work in the Exchange Troubleshooting Assistant (Extra.exe) tool on an Exchange 2010 Edge Server.
When you use the message tracking task in the Microsoft Exchange Troubleshooting Assistant (Extra.exe) on an Exchange 2010 Edge server, you get the following error message:
The process “ExTRA (PID=1928) has been initialized as unknown multiple instance type un-expectedly.
This is a known issue with Exchange 2010 server running as Edge Server. Microsoft is working on a hotfix for this. The current work around is to use the Get-MessageTrackingLog cmdlet in Exchange Management Power Shell (EMS) on the Exchange 2010 Edge Server. For more information on this issue, see Microsoft KB977957 at http://support.microsoft.com/kb/977957
Zero Day IT - Peter V Nguyen 
i have same error instead of PID=1928 there is PID=1724