Those tooltips are created yb the SweetTitlesTooltips plugin and it expect the CSS file to be in
http://www.yourdomain.com/wp-content...weetTitles.css but looks like its not there.
You probably either didn't upload the CSS file, or you uploaded the plugin in a wrong location. I.e. you uploaded the xxxxxx.php instead of the whole plugin directory.
Once you have fixed that you can edit that CSS file.