Cisco devices can use a proprietary encryption algorithm to encrypt the password for enable mode and vty lines. This kind of encryption is used when "service password-encryption" has been enabled on the device and produces, what they call, Type-7 passwords.
This feature allows you to decode encrypted passwords from configuration files.
This tools cannot decode Cisco Type-5 passwords. You can use Cain's IOS-MD5 Cracker to do that.
Simply cut and paste the encrypted password into the dialog; the decoder will do the rest.