I'm writing the code to send email using the examples. I'm including DKIM so I have created a certificate and downloaded it and placed in my web root folder.
I'm attempting to get the public key with the code.

Certificate oCert = new Certificate();
    oCert.Load("C:\\Users\\Nigel\\Documents\\Visual Studio 2015\\Projects\\TonerPeopleWebSite\\TP_Web\\tonerpeopleDKIM_Local.txt", "MyCertificatePassword", Certificate.CertificateKeyLocation.CRYPT_USER_KEYSET);
    Console.WriteLine(oCert.PublicKey);

However, the oCert.Load raises and error "An error occured during an encode or decode operation".
I have tested the password when installing the certificate locally and all is fine with that.

Can anyone make any suggestions what is wrong?

could you send your certificate and password to support@emailarchitect for assistance? It seems that your file is not in p12 format.

Finally problem is solved (invalid file path)