why nginx not support php new $class()

[chinafirefox]

Hi everyone:

the error is 
502 Bad Gateway
nginx/0.7.65

my php scripts:

$RTR =& load_class('Router');  ---->pass 
.......
$class  = $RTR->fetch_class(); ---->pass
......
$CI = new $class();    ---->nopass my breakpoint step here

give me some advice ,friends,tks

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,213761,213761#msg-213761