So, you downloaded and installed the iTunes beta for iTunes Match without first thinking about the consequences. No sweat.
If you've since tried to downgrade your iTunes beta back to a publicly released version of iTunes, resulting in the horrible ‘”iTunes Library.itl” cannot be read because it was created by a newer version of iTunes’ error message, don't succumb to tears just yet; we've got a fix that might just work.
Save the precious iTunes library that you've spent hours upon hours massaging to perfection, and tune in to the following video tutorial...