Can someone tell what this error mean when I'm trying to start apach on FC3.

Starting httpd: Syntax error on line 6 of /etc/httpd/conf.d/php.conf:
Cannot load /etc/httpd/modules/libphp4.so into server: libgmp.so.3: cannot enable executable stack as shared object requires: Permission denied

first, what is on line 6? did you edit something?
second did you install php4?
third are you trying to start httpd as root?

bosewicht,

line 6 in php.conf file is:

LoadModule php4_module modules/libphp4.so

Yes. php-4.3.11-2.8 is installed on the server.

Yes, I'm starting httpd as root.

take a look at the log and see what the error is. maybe it is a little more descriptive on what is going on.

disable selinux

bosewicht,

this is all I got from message log:

Jan 10 17:23:45 ux-mail kernel: audit(1136935425.010:17): avc: denied { execmem } for pid=18217 comm="httpd" scontext=root:system_r:httpd_t tcontext=root:system_r:httpd_t tclass=process
Jan 10 17:23:45 ux-mail httpd: Syntax error on line 6 of /etc/httpd/conf.d/php.conf:
Jan 10 17:23:45 ux-mail httpd: Cannot load /etc/httpd/modules/libphp4.so into server: libgmp.so.3: cannot enable executable stack as shared object requires: Permission denied
Jan 10 17:23:45 ux-mail httpd: httpd startup failed

dc2447 has a point, i forgot about selinux.

Well,

I disable selinux and httpd is able to start fine. Now, I just need to figure out what I need to do to get apache to work with selinux on. Thanks for all you help dc2447 & bosewicht

For those who need direction on how to enable block services in selinux. Here are the steps:

1. install selinux-policy-targeted-sources
yum -y install selinux-policy-targeted-sources
2. turn off selinux temporary
setenforce 0
3. start the service which will fail and an error log will be created on /var/log/messages
service httpd start
4. ran audit2allow to allow access in selinux
audit2allow -l -i /var/log/messages >> /etc/selinux/targeted/src/policy/domains/misc/local.teaudit2allow -l -i /var/log/messages >> /etc/selinux/targeted/src/policy/domains/misc/local.te
5. reload selinux
make -C /etc/selinux/targeted/src/policy/ reload
6. turn selinux back on
setenforce 1
7. start httpd service
service httpd start

this will resolve your problem. If not, repeat the above steps.