To fix this and several similar error messages:
Line 101 becomes:
$meta_seo = isset($post->ID)?get_post_meta( $post->ID, $this->parameter['name_option']."_metabox" ):'';
Line 384 becomes:
if( $des_aut = get_the_author_meta( 'description', isset($authordata->ID)?$authordata->ID:0 ) ){
Line 392 becomes:
<meta property="og:title" content="'.(isset($authordata->display_name)?$authordata->display_name:'').'" />
Line 394 becomes:
<meta property="og:url" content="'.get_author_posts_url( isset($authordata->ID)?$authordata->ID:0 ).'" />
Line 408 becomes:
<meta name="twitter:title" content="'.(isset($authordata->display_name)?$authordata->display_name:'').'" />
Line 533 becomes:
$author = isset($authordata->display_name)?$authordata->display_name:'';
