If you have forgotten your master password, as part of the security measure there is no way for anyone to recover it, not even us. You can, however, reset the vault to create a new one.
TIP: Doing the following will delete all of your passwords in the vault. Only do this as a last resort if you can't remember your Master Password.
Quit TotalAV
Go to your Documents
Find and Delete the folder TotalAV
Restart your Computer
Open TotalAV
You will now have a fresh version of Password Vault to use.