Exchange Server 2007 Transport Errors — SMTP Session Hangs

Hi
I want to make some changes to the server (writing a Transport Agent). While trying to install it, I am receiving some errors.
While trying to connect to the SMTP server, the whole session just hang all of a sudden after finishing the DATA section.
I don’t know what happened. Then I cripple the transport agent and next uninstalled it before restarting the server.
The problem is:
In the Event Viewer, four of the same errors show up:
Source: FSCTransportScanner Category: Scan Error Event ID: 5021 Description: Unable to retrieve internet monitor interface.
I am unable to fix it. Need help.
Thanks.
