The Railo installer does a great job across multiple operating systems but it is not completely infallible (although it does come awfully close). The installer will complete, but there are two extra steps you will need to take to get things up and running smoothly on Arch Linux.
First, fire up your favorite editor and open up /opt/railo/tomcat/conf/server.xml and scroll down until you find the HTTP connector block. You will see something along the lines of “@@tomcatport@@” listed where the port should be. Replace this value with whichever port you want Tomcat listening on.
Next we need to move the railo_ctl file from /opt/railo/ to /etc/rc.d/, this is the folder that Arch Linux uses for its daemon services instead of /etc/init.d/ like Debian and RHEL systems use. Once the file is in there, chmod 0755 /etc/rc.d/railo_ctl to set the permissions on the file.
Finally, if you want Railo to startup automatically on boot there is one final modification to make. With your favorite editor open up /etc/rc.conf and add railo_ctl to the DAEMONS line and it will now start when you boot your machine. You should now be ready to start Railo up, just sudo /etc/rc.d/railo_ctl start and you should be in business.