You should describe problems in detail. For example, what algorithm was used to encrypt the file.
If you encrypted the file with a key-file using a strong encryption algorithm you won't be able to decrypt the file without this key-file. The password for the key-file won't help you if you don't have the file. This is a kind of two-factor authentication.
You can not regenerate the key-files. They are generated with random numbers. It is good that you cant regenerate them. If you would be able to do this an attacker could be able to.
The only way you can get back your files is trying to restore the key-files. If you are lucky you are able to restore them from your hard drive.
Your lesson learned should be to back up your keys.