Thanks for the report! This has been fixed for 0.3 which will come out in 4 days for the public! :) Hopefully you can open it again afterwards, otherwise that'd be a bummer. Maybe you can report back on that topic, thanks!
Eh, i just rolled back to before the error (which resolves the inability to reopen it) before saving. Definitely looking forward to seeing what's in there, though! ^_^