upstream prematurely closed connection while reading reading response

Hi guys,

I have run into an odd problem on my nginx server which I am unable to solve. I have searched almost everything on the google but nothing seems to be specific to my problem or just doesn't solve it for me.

When I try to execute my php script, after few seconds it gives me the 502 Bad Gateway.

While in the nginx error log the following line is logged.

##########################################
2013/07/02 20:48:17 [error] 23240#0: *14469 upstream prematurely closed connection while reading response header from upstream, client: XXX.XXX.XX.XXX, server: abc.com, request: "POST /members/admin/useradd.php HTTP/1.1", upstream: "http://XX.XX.XXX.XX:7080/members/admin/useradd.php", host: "abc.com", referrer: "http://abc.com/members/admin/useradd.php?userid=150"
##########################################

Any help would be highly appreciated.

Thanks in advance.