Shoutbox

In addition to the above, check the registry at HKEY_CURRENT_USER\Software\Patchou\Messenger Plus! Live\GlobalSettings\Scripts\<scriptname>
as there may be one or two settings left over after removing the script. Try removing these (if any) and reinstall the script.

If that still doesn't work, look at the script debugger to see if there are errors that are stopping it from starting properly.