I just did a quick check, and I'm not using the protocol anywhere in SPServices except in the SOAP namespaces.
Are you referencing the js files with a protocol? See this post:
http://sympmarc.com/2013/02/07/referencing-jquery-jqueryui-and-spservices-from-cdns-revisited/
M.
Are you referencing the js files with a protocol? See this post:
http://sympmarc.com/2013/02/07/referencing-jquery-jqueryui-and-spservices-from-cdns-revisited/
M.