Accordance crashing on iPad: "I/O Error #-43 in the file "/Sample notes v2.amynotes" ??

[DiscipleDojo]

This is the message I'm getting on my iPad whenever I try and open it. It just started last night as I was trying to sync Accordance between my new macbook, an old macbook running OS X El Capitan, and my iPad.
 

I know it's a syncing issue, but I am not apple-literate or techy enough to know what is wrong, and after literally spending the last 10 hours trying to get Accordance working on 3 three devices, I'm at my wit's end, I'm afraid.

 

Any help?