I meant the key, not the data, my bad. I was trying to understand why the server is crashing and I used your nVault editor to check the vault file while the server was crashing on startup. The key value was blank and deleting it fixed the problem (deleting the entire vault file did the job as well). The crashes stopped for good after checking if the key is empty and not saving if it is.
Now, I don't know if it was really the key that's empty or the entire vault entry was corrupted, but I do know that a simple if(!szKey[0]) return check fixed it.