Ok, so in your wp admin panel you have a plugin installed. And in settings -> "insert headers and footers" you inserted some markup:
<!DOCTYPE html> <html> <body> <footer> <table> <tr> <p style="color:#5c5c5c;margin-bottom:13pt;margin-left:23pt;font-size:8pt;font-family:'helveticaNeue-Light'">© Francesco Giordano - All rights reserved - <a href="http://google.de" style="color:#5c5c5c">Impressum</<a></p </footer> <footer> </body> </html>this is not good html for putting it in the footer.
your </<a> tag doesnt close right, your </p tag doesn't close right, your <footer> tag opens again at the bottom. you shouldn't use opening "<!DOCTYPE html><html><body>" tags for html that is beneath the other markup. the opening <html><body> tags are just for the head, when the html starts.
also you could use lay option's capabilities for this.
There is the footer feature. http://laytheme.com/documentation.html#footers
Or there is the html at bottom field in "lay options" -> "custom css & html" -> "custom html at bottom"
So in short, i think your lightbox links to google cause your footer markup is invalid. You can remove it and use lay themes footer feature instead :).