Failed to open project from C2

Has anyone else encountered this error exporting a capx from C2 and trying to open in C3?

thanks for the hint! I checked the console and see this:

[Project] Exception opening: Error: expected a child with tag name 'animation-folder'

at ǃ_.ǃQr.Element.ǃZH (main.js:2)

at Function.ǃ_rI (main.js:63)

at Object.i.push.ǃ_.ǃaL [as ǃbBz] (main.js:63)

at n (main.js:2)

at s (main.js:2)

What exactly does this mean?

I'm using the Spriter plugin in both C2 and C3, so wondering if it has to do with that?