LumenVox Speech engine and Libjs dependency

Not 100% sure this is the correct place to post this message but anyway:

LumenVox sppech engine requires Libjs. Libjs, the Mozilla implementation of JavaScript, and it is not available in the CentOS yum repositories, so you will have to get it separately if you do not already have it.

Being a fairly limited user. I have download the RPM: from :http://dag.wieers.com/rpm/packages/js/

I download: js-devel-1.60-1.el5.rf.i386.rpm into a directory /etc/LumenVox

I did a:

yum install js-devel-1.60-1.el5.rf.i386.rpm

but this did not work.

Can anyone briefly help me on what to do to get libjs loaded.

many thanks