If /usr/local/squid26s9TP/var/logs is given a group writable permission orif the PID file is given at /var/run which is owned by root:root then theissue disappears.Odd.. is there perhaps a selinux policy or similar playing ghosts with you?SElinux is disabled on my system. I have tested on both FC5 and FC6 and same problem. Let me try somemore things and will post you.
My quick analysis showed that the issue is caused by the capset() call in leave_suid(). Not sure how it affects creating the pid file, though this happens well before the leave_suid() call.
-logu