Darragh Ó Héiligh blog and accessibility guides

I've not had this problem my self however I seem to have found a solution.

The problem is caused by an update to AVG.  To temporarily work around this until a fix is released to AVG, do the following:

IN AVG options, Web Shield, Disable the option for instant messaging protection.

It's as simple as that. 

If you want to determine how I found this, do the following: (Instructions obtained via a Microsoft KB article.)

To gather the connectivity log, please follow steps below:

1. If Messenger is running, right-click the "MSN Messenger" icon in the notification area at
the far right of the taskbar, and then click "Exit."
2. Delete the already existing connection log file, if it is available:
a. Start Messenger but do not sign in.
b. Click "File," and then click "Open Received Files" on the "MSN Messenger" menu to go to
the My Received Files folder.
c. Look for the MsnMsgr.txt file, and then delete it. To do this, click the file, and then
press DELETE.
d. Look for the MsnMsgr.txt file, and then delete it. To do this, click the file, and then
press DELETE.
3.Enable connection logging if it is not already enabled.

a. Start MSN Messenger but do not sign in.
b. On the "Tools" menu, click "Options."
c. In the "Options" dialog box, click "Connection."
d. Under "Connection Logging" make sure that the "Save a log of my server connections to help
troubleshoot connection problems" check box is selected.
e. Close the "Options" dialog box.
4. To sign in to MSN Messenger again, click "Sign In." and wait until the sign-in error
appears.
5. To access the new connectivity log file (MSNMsgr.txt) follow steps in Step 2.