In order to install pactester gracefully without building packages by hand, follow these steps

• Fetch the “js” and “js-devel” RPMs for your architecture from DAG : http://dag.wieers.com/rpm/packages/js/
• Install both RPMs
• Use CPAN to install the “Log::Log4perl” and “JavaScript::SpiderMonkey” CPAN modules

Here are the exact commands for a RHEL 4 system

# Download the SpiderMonkey js and js-devel RPMs from DAG
wget http://dag.wieers.com/rpm/packages/js/js-1.5-1.2.el4.rf.i386.rpm
wget http://dag.wieers.com/rpm/packages/js/js-devel-1.5-1.2.el4.rf.i386.rpm
# install the RPMs
rpm -ivh js-1.5-1.2.el4.rf.i386.rpm js-devel-1.5-1.2.el4.rf.i386.rpm
# Install the two CPAN modules with CPAN
cpan -i Log::Log4perl JavaScript::SpiderMonkey

The JavaScript::SpiderMonkey CPAN module requires the js and js-devel packages