Had the same problem - application event log flooded with this silly informational event.

This is for Blackberry Enterprise Server Express 5

Found the solution - simple registry change as per below:

HKEY_LOCAL_MACHINE\SOFTWARE\Research In Motion\BlackBerry Enterprise Server\Logging Info\BlackBerry DBNS

The default value for "DebugLogLevel" is set to 4 (which I think is the max)

I set mine to 1 and it seems to have corrected this problem.