Found the reason and workaround. The reason was a plugin conflict with, in my case, “Video Sidebar Widgets”. The workaround is to modify “simple-author-box.php” (in plugin root) and “sabox_author_box.php” (in plugin “core” folder). I renamed the php variable $options to $sab_options and everything works perfectly.
Thanks for this great plugin.
Hope this could help somebody.
