The reason it failed to import your sounds into MsgPlus! Live is because this version was specifically wrtten for MsgPlus 3.xx.
MsgPlus! 3.xx stores its sound information in the registry under the key:
whereas MsgPlus! Live stores it under:
HKEY_CURRENT_USER\Software\Patchou\Messenger Plus! Live\GlobalSettings\CustSounds
and so whenever you run the tool it will only write to the MsgPlus! 3.xx registry setting (hence why the sounds didn't show up in MsgPlus! Live)
If you had all the sounds in your library in 3.xx, then installed WLM + MsgPlus! Live, I'm not sure why your sounds weren't automatically imported though...
I hope you know what I mean, I'm not very good at explaining stuff
Maybe its time the tool was updated for MsgPlus! Live support Cookie?