first of all i personaly don't like small programs with instalation systems... they tend to install unknown other "things" and change windows config and stuff like that. and this one realy does. that error message on installation makes me think what went wrong there.... i would rather prefer to install it manually.
when i opened messenger after installing your plugin a window appear saying something about supporting you and stuff... and that's too agressive for me. i'm sorry, i understand your effort on making this, but that dialog appearing everytime i open messenger is such a bad ideia. make that info on the plugin config window.
and your plugin takes 20 times more memory than msgplus! itself.
6,3mb is still way too much (i own a very old toaster
).
i've found out this one that takes less memory, works pretty fine and is defenetly less evasive to my system. check it out