Restore (large) Library from Vault fails with no error message

I just got a new hard drive because my previous Aperture drive started glitching to the point where a straight copy of my old library to the new disk fails, so I'm being forced to rebuild it from my latest vault backup.

I created a new, blank library to import the vault contents into, but when I do File --> Vault --> Restore Library... and select the appropriate vault (and confirm), it starts a progress bar saying "calculating disk space" and then that goes away and... nothing replaces it.

There's no error message, there's no progress bar, there's no high CPU usage from Aperture and, even more frustratingly, nothing helpful in the system log.

I do get the following message in the system.log, but it doesn't make much sense to me:

Dec 26 21:41:09 Alice.local Aperture[3634]: view service marshal for <NSRemoteView: 0x7f97be4bf9e0> failed to forget accessibility connection due to Error Domain=NSCocoaErrorDomain Code=4099 "Couldnâ&#128;&#153;t communicate with a helper application." (The connection was invalidated from this process.) UserInfo=0x600001879100 {NSDebugDescription=The connection was invalidated from this process.}
    process/thread/queue: Aperture (3634) / 0x122d10000 / com.apple.NSXPCConnection.user.endpoint

This is a rather large library, about 800GB. No referenced masters, everything is inclusive.

And I would really, really like it back.

Help?