You're not alone. I've been seeing this error for months, and Label Creator 8 crashes a lot too. The problem shows up when opening version 7.5 JWL files as well as version 8.0. Some files reopen okay, and I can't figure out what causes some to be unreadable and some to be okay. I hope someone figures it out, because I sometimes spend nearly an hour designing a complicated label, and it's sure a pain when the JWL file can't be opened later.