Of course you should use the latest version of fairuse4wm, i.e.fu4m 1.3 fix-2. The problem is that it doesn't work with the latest IBX.

If you're forced to upgrade, I don't really see any option other than using lossy DRM removal software.

If you upgraded your IBX by accident, you can downgrade your Windows Media Player or install another copy of Windows (onto a virtual machine or as a standalone copy). Make sure not to update your Windows or at least do it selectively.