We have deployed our rails application on on nginx and passenger.Intermittently pages of application get loaded partially.There is no error in application log.But nginx error log shows the following :

2011/02/14 05:49:34 [crit] 25389#0: *645 open() "/opt/nginx/proxy_temp/2/02/0000000022" failed (13: Permission denied) while reading upstream, client: x.x.x.x, server: y.y.y.y, request: "GET /signup/procedures?count=0 HTTP/1.1", upstream: "passenger:unix:/passenger_helper_server:", host: "y.y.y.y", referrer: "http://y.y.y.y/signup/procedures"