What was the message for the first song?Can you please check if the song isn't being held open by WMP itself? You can do this by opening WMP's Play tab - the currently opened song will be highlighted (it doesn't necessarily have to be playing).Which version of WMP Plus were you using before updating? It would surprise me if this got introduced with version 2.6 since there weren't any changes to the tag editor.
Yes, you can change the limit by editing the IncludeSetMaxItemCount registry value in HKEY_CURRENT_USER\Software\BM-productions\WMP Plus and restarting WMP. But note that the performance of browsing the library may suffer if the limit is too high.
Thanks for the report - KB3000850 is indeed the most likely culprit. I'll look into this as soon as I find some time.
Which version of Windows are you running? 32-bit or 64-bit?Please make sure that WMP Plus is still loaded - it should be listed and checked in WMP's Tools - Plug-ins menu (press Ctrl+M if you don't see the Tools menu).When the menu items don't appear, where exactly in WMP's user interface are you right-clicking a song?
Just to prevent any misunderstandings, WMP Plus is fully supported and should work fine on 64-bit Windows Vista/7/8.Unfortunately, it's currently not possible to completely turn off Party Shuffle. This is intentional because the feature is only really active while the Party Shuffle playlist is playing. If you don't need it then you can just ignore this playlist. But one of the next versions of WMP Plus probably won't recreate the Party Shuffle playlist anymore, so then you will be able to just remove the playlist once.