Probably not what you want to hear but since running GNU/Linux is all about performance, protecting assets and providing services in a continuous, stable and secure way you must know Red Hat Linux maintenance and errata support ended on April 30 of 2004 for all YES ALL Red Hat Linux releases (not RHEL). The version you installed is obsolete, no longer maintained and unsupported. This means you miss out on all the new technology that's been around for ages, all the bug fixes and all the security updates. Unless you have the knowledge and time to maintain this setup yourself to keep it from (doing) harm, keeping your machine attached to the Internet makes it a hazard not only for you but for the whole community. So unless you're a seasoned admin and will actively invest time supporting legacy applications on that platform please plan your migration and make it soon. If you like the effort Red Hat puts into certification, ISV acceptance, support longevity and stability of RHEL but don't want to pay for RHEL then you could run CentOS (current is 5.2). If you like what RHL provided then you could run Fedora (stable seems 9 right now). Else check out the many "choose a distro" threads or the megathread at LQ.
Wrt your question, run 'chmod 0755 /usr/sbin/sendmail' then try again. If that doesn't fix things look at the access rights of the directory the binary is in, extended attributes ('lsattr') or the mount arguments if /usr is on a separately mounted partition.
Last edited by unSpawn; 08-01-2008 at 03:41 AM.