Windows Mobile ActiveSync:

When a meeting invitation containing an attendee email address 27 or more characters long is accepted, a repllog.exe error displays on a Windows Mobile device. 
The error reads "A problem has occurred with repllog.exe."

There is no current solution to this issue, however, it does not affect the device's ability to send the meeting response. 

A workaround for this is to suppress error reporting on the device. 
Select Settings > System (tab), open Error Reporting and select "Disable error reporting"