Weird I get the same thing going on, but found this info
When the BlackBerry Controller is restarted, or the log cycle restarts
, the following error is logged in the Application log:
[CFG] Controller won't generate userdump files. Userdump.exe not found.
The BlackBerry Enterprise Server is configured to use the userdump.exe when an error occurs.
Download and install User Mode Process Dumper 8.1 utility from Microsoft Corporation