In PGP Desktop I do File / Import and then I import my TEXT File 1st. The trust will not allow me to set to IMPICIT. Then I do File / Import and then I import my 2 keyrings that are associated. The one titled "pubring" imports fine, When I try and get the other kering titled "secring" it says, "PGP is unable to import any keys, certificates, or groups from selected file".
Let me know if you need more info. Thanks.