Hi x_SCC_x,
If you go to
the download page, you'll see that for users of
Windows Live Messenger 2009 beta there's a link for a compatible beta version of Messenger Plus! Live.
Download and install that, then Plus! will work
Note: It's only a beta, meaning that it's not completely finished. So if you experience any problems it's recommended you downgrade Windows Live Messenger to the latest stable version (currently 8.5).
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