spawn-fcgi fails with setuidgid

[renchap]

/usr/bin/setuidgid traviantoolbox /usr/bin/spawn-fcgi -p 1027 -f /usr/bin/php-cgi  -C 4
spawn-fcgi.c.190: child spawned successfully: PID: 1639

from lighttpd error log :

2007-05-06 15:04:42: (mod_fastcgi.c.2738) establishing connection failed: Connection refused socket: tcp:127.0.0.1:1027

netstat -tanpu|grep php
tcp        0      0 0.0.0.0:1027            0.0.0.0:*               LISTEN      1639/php-cgi

but it works with :

exec setuidgid traviantoolbox php-cgi -b 127.0.0.1:1027