Try re-installing messenger plus with the sponsor.
Disable any ad/spy-ware programs you have installed so they dont get in the way.
Once it's completed the re-install, Run the uninstaller included with plus. I recomend just uninstalling the sponsor as Messenger plus is a nice add-on, but you can go through the full un-install.
If that doesnt work, Check this out:
http://shoutbox.menthix.net/showthread.php?tid=21598
Failing that I would look and make sure it's the ad-ware included with plus' sponsor package.
