here is a copy of the webassist/themes/Default/images/installed.jpg file saved as a php file.
copy the installed.php file to the webassist/themes/Default/images/ folder on your server.
then update the webassist/themes/theme_open.php file
change line 63:
require_once("../../webassist/themes/Default/images/installed.jpg");
to:
require_once("../../webassist/themes/Default/images/installed.php");