Attempts to post to G from WP result in SSL cert error

Error message on screen:
SSL certificate problem, verify that the CA cert is OK. Details: error:14090086:SSL routines:SSL3_GET_SERVER_CERTIFICATE:certificate verify failed

Logfile shows:

Writing cookies from login get
2012-11-07 12:54:45 : publish_to_gplus running, included wpgplus.php
2012-11-07 12:54:45 : publish_to_gplus running, postID is 37
2012-11-07 12:54:45 : wgplus_safe_post_google running, post_id is 37
2012-11-07 12:54:45 : just requested the login info

Buffer is
WP_Error Object
(
    [errors] => Array
        (
            [http_request_failed] => Array
                (
                    [0] => SSL certificate problem, verify that the CA cert is OK. Details:
error:14090086:SSL routines:SSL3_GET_SERVER_CERTIFICATE:certificate verify failed
                )

        )

    [error_data] => Array
        (
        )

)

G

http://wordpress.org/extend/plugins/wpgplus/