Hi Nathan,
I’ve downloaded from the URL in your post, and it sent me a valid zip file. So, I think something is up in your WP install – you might want to check your disk space (though that’s only one possibility).
Anyway – I’ve sent you the plugin by email, including the Migrator add-on. So, if you de-install your existing plugin, and upload this one, then all should be well – no downloading required.
I notice you posted a support request with identical content to this forum post – that’s redundant; both come through to us. (Detecting + deleting duplicates just slows us down).
Best wishes,
David