hey i'm sorry my english isn't very well, because i am german
i also have the new version of the windows live messenger (2009) and Messenger Plus! live and i have the same problem like the others had.... i also tried your solutions, but it didn't work at all... i have to say that i have not "threatfire". i also uninstalled windows live messenger and Messenger Plus live a thousand times-.- but it didn't help.
maybe you have another idea, why it does not work...