Fatal Error when attempting to activate 1.5.7

I was reading on this plugin and sounds like the one that I have been searching for but when I attempt to activate it then I get the following Fatal Error Message.

Fatal error: Cannot redeclare class lessc_formatter_compressed in refugeag.org/wp-content/plugins/mobilechief-mobile-site-creator/lib/lessphp/lessc.inc.php on line 3406

http://wordpress.org/extend/plugins/mobilechief-mobile-site-creator/