Once you get you iTunes Library back to where you like, make a copy of iTunes Library.itl file, and put some where you remeber where it is at.
I have like the Devleoper Preview version of Mavrick on a external Hard Drive and every time and I listen to itunes on Mavrick, and I got back to the other OS, and when I try and open iTunes it tells me that the library was open with a newer version of itunes and it lists the file above, plus it also tells me to download a newer version of itunes, but i do have the current itunes.. So I figured something out copy that file I list above and, and since I made a copy of that file, so the last time i listen to iTunes on Mavrick, and switch back to the other OS version, I went to Music, iTunes and delete the old version of that file and then took the version that I copied and moved back in. and then I tried to open iTunes, and it worked I did not get the error