I don't get this, heard this from two people now, but as far as I can tell there are no changes to the iTunes SDK, and iTunes+ still works fine for me.
I do have a slightly updated version I've been working on, but I don't think I've changed anything that would make that kinda difference!
But I'll look into this, sort out this version for release and such.
BTW, are you using the beta version posted on the forum? If not, try it, just in case it helps:
http://msig.info/itunesplus/script/iTunes+%20BETA.plsc