Dispatcher failed to map segment from shared object permission denied

The Problem
Although your dispatcher mod file is there, you can't seem to load the mod_dispatcher file.

The Solution
First, double-check in your httpd.conf file that you are actually pointing to the right place. Remember that your ServerRoot is the prefix appended to the mod_dispatcher.so path file.

If the file is where you would expect it to be, check that the user you are running apache under has the right to see the file.
ls -al

will show full permissions of the directory listing.
chown group:user will change the file ownership

chmod 755 will give read and execute rights to the owner, the group and everyone.

Finally, if you are running Red Hat Enterprise Linux (RHEL), it is possible you are running selinux, and don't even know it.

Have a look under /etc/sysconfig/selinux.

In the file, you may see selinux=enforcing.

If this is the case, then selinux probably doesn't like the dispatcher mod and is blocking it. You can drop the permissions down to permissive or disable to remove it entirely, but check with your systems administrator, as this will have other effects on the system.