I fixed mine by removing the reference to the developer’s server.
In pinterestbadgehelper.php replace
$this->regexpurl = "http://www.skipser.com/test/pinterest-badge/regexp_".$this->regexp_filever.".txt";
with
$this->regexpurl = plugins_url("pinterest-badge/regexp_".$this->regexp_filever.".txt");
This will use the file regexp_1.1.txt that comes bundled with the plugin.
I have a fix for the initial question:
Replace the following in wpgft-loader.php line 390 and wpgft_processOrder.php line 314
if( function_exists('wp_nonce_field') ) $formCode .= wp_nonce_field($nonceID);
with
if( function_exists('wp_nonce_field') ) $post_content .= wp_nonce_field($nonceID, "_wpnonce", true, false);
This will prevent the <input> field from being output before the <!DOCTYPE
