GPA and hkps

[John]

Hello.  In this instance I am running 64-bit Win7, and I have GPA installed 
with Gpg 2.0.17, which came from here: http://www.gpg4win.org/. In my 
configuration file are these two lines:

keyserver hkps://zimmermann.mayfirst.org
keyserver-options verbose ca-cert-file=%appdata%\gnupg\mfpl.crt


And I do have that certificate in the folder. However, I get an error 
message when I use GPA to try retrieving a key. The message states this: 
"There is no plugin available for the keyserver protocol you specified." 
What am I missing? Thanks.

John