i realize this message was posted in july...and has since, perhaps, been resolved; HOWEVER, i had the same issue after configurator crashed on me this past monday. i did NOT have a back up (of course) of my data (which included VPP codes)...and so was pretty invested in figuring out how to get it working again. i managed to locate the folder with the "previous library" (it was actually in ~/Library/Containers/com.apple.configurator/Data/Library/ApplicationSupport/com .apple.configurator/PreviousData), but could not figure out how to get the app to open using the previous library. i called apple's technical support to see if they could help me with this part. i explained my situation...and was told there was nothing i could do to fix it without having a backup--i would basically have to start over and lose all the data/VPP codes. at this point, i decided that if i had to start all over again, it couldn't hurt to play around with it myself--i couldn't possible make it WORSE. and, amazingly enough, what i did appears to have worked.
so here's what i did:
1. i went to the folder with the current library file (~/Library/Containers/com.apple.configurator/Data/Library/ApplicationSupport/co m.apple.configurator/) and dragged the file named "AppleConfigurator.storedata" to the trash.
2. then i tried taking the similarly named file (AppleConfigurator.storedata) from the previous data folder (~/Library/Containers/com.apple.configurator/Data/Library/ApplicationSupport/co m.apple.configurator/PreviousData) and dragging it to the current folder. THAT didn't work...so i put it back and tried dragging the file named Users.storedata from the previous folder to the current one. tried opening the app again...no luck.
3. finally, i put all the "previous" data files back in the folders where they had been, and dragged the original AppleConfigurator.storedata file out of the trash and into the current folder. when i tried opening the app again, it opened with all my data. whoo-hoo!
i don't know if anyone else will find this at all helpful, but i thought i would post it because i was near tears at the realization that i had lost everything i had done with the 25 ipads i have...and about $2000 worth of VPP codes.