Do you only have one copy of your wallet.dat or do you have a backup as well? This sounds like your wallet is corrupted. What occurs when you do the following?

1. Delete all CBX files and folders (including roaming) except for your wallet.dat
2. Move wallet.dat to a folder on your desktop. You should have no CryptoBullion files anywhere on your machine at this point. If not, delete the remaining files/folders (except the wallet.dat folder you have manually copied to desktop.
3. Download a new version of the Vault.
4. Launch new Vault, download bootstrap and allow to sync with the newly created wallet.dat. You should not be getting a runtime error at this point.
5. Once completely synced, close Vault, replace the wallet.dat with your old one from the desktop and reopen Vault. What occurrs?
6. Try your other wallet.dat copies as replacements as well to see if any of them work (assuming you have backups).
7. Please report back outcome.