Restoring vault gives error that vault never updated but it was. Why won't it restore?

My hard drive crashed and I am trying to restore my library from my exterior harddrive where I have my vault. When I go into Aperture and try to restsore library it says my vault "has never b een updated" but the vault file shows it was updated a week ago, which it was. What am I doing wrong? I had over 76,000 raw photos in my library. My vault file is 94 GB.