Whoops. Bad judgement. 
In that case, youāre better off using MSN 4.6 or lower. If my memory serves me correct, Windows Messenger 4.7.2009 uses the Tweener method of authentication, and I guess something goofs up when that happens. Since I am sure that MSN 4.6 and below use MD5 authentication, it has much more of a chance of working properly.
Hereās the ZIP file with the MSN 4.6 installer: mmssetup.zip (922.7 KB)
Just uninstall Windows Messenger, install MSN Messenger 4.6, patch is as necessary, and give it a go. Iād like to see the results. 