PLEASE HELP - Can not access vault files

Well, SecureAccess will only run from the USB drive.  How/why it was on your harddrive is unknown but the error is understandable.

Why the vault on your USB drive is corrupt I would guess is due to your not removing the drive Safely and it’s file allocation table is corrupt.  Try running chkdsk or something similar to see if it will file the error.

Good luck.