That problem should not have anything to do with Messenger Plus! (Messenger Plus! does not interfear with anything which could fail a login attempt like that).
That error usually means you also have troubles with automatic updates of Windows. It could also be that you did not had everything properly installed in regards to Windows Live (Messenger), eventhough it may have seemed so.
As such, the first thing you should do is go to
Windows Update and make sure you have installed _all_ the available updates and fixes. Remember to reboot and after each reboot you must check again if there are no more updates available.
After all that you could try to reinstall Windows Live Messenger 2009. First
redownload it again from its official website, and then do a complete re-install (don't use patched or tampered installers, use the official ones).
/ 
