Why my server (nginx+php(fastcgi) )can't execute cgi?

[zhxd]

I sourcecode compile install FCGI-0.67,and install nagios.
I think the CGI can execute,now.
But I found that,when I visit cgi url,Web browser tell that:502 Bad
Gateway
I found error in nginx error.log：
[code]
2010/08/16 14:07:51 [error] 1720#0: *3 connect() to
unix:/usr/local/nginx/logs/nginx-fcgi.sock failed (111: Connection
refus
ed) while connecting to upstream, client: 219.139.240.250, server:
nagios.whidc.net, request: "GET /test.cgi HTTP/1.1", upstream:
"fastcgi://unix:/usr/local/nginx/logs/nginx-fcgi.sock:", host:
"nagios.abcd.net"
2010/08/16 14:08:12 [error] 1720#0: *3 connect() to
unix:/usr/local/nginx/logs/nginx-fcgi.sock failed (111: Connection
refus
ed) while connecting to upstream, client: 219.139.240.250, server:
nagios.whidc.net, request: "GET /test.cgi HTTP/1.1", upstream:
"fastcgi://unix:/usr/local/nginx/logs/nginx-fcgi.sock:", host:
"nagios.abcd.net"
2010/08/16 14:08:43 [error] 1720#0: *3 connect() to
unix:/usr/local/nginx/logs/nginx-fcgi.sock failed (111: Connection
refus
ed) while connecting to upstream, client: 219.139.240.250, server:
nagios.whidc.net, request: "GET /test.cgi HTTP/1.1", upstream:
"fastcgi://unix:/usr/local/nginx/logs/nginx-fcgi.sock:", host:
"nagios.abcd.net"
2010/08/16 14:08:51 [error] 1720#0: *3 connect() to
unix:/usr/local/nginx/logs/nginx-fcgi.sock failed (111: Connection
refus
ed) while connecting to upstream, client: 219.139.240.250, server:
nagios.whidc.net, request: "GET /test.cgi HTTP/1.1", upstream:
"fastcgi://unix:/usr/local/nginx/logs/nginx-fcgi.sock:", host:
"nagios.abcd.net"
2010/08/16 14:09:11 [error] 1720#0: *3 connect() to
unix:/usr/local/nginx/logs/nginx-fcgi.sock failed (111: Connection
refus
ed) while connecting to upstream, client: 219.139.240.250, server:
nagios.whidc.net, request: "GET /test.cgi HTTP/1.1", upstream:
"fastcgi://unix:/usr/local/nginx/logs/nginx-fcgi.sock:", host:
"nagios.abcd.net"
[/code]


where has the mistake?:(

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,119929,120217#msg-120217