To check which Perl and PHP modules are installed on your 123-reg hosting package, please do the following:
Login to your 123-reg control panel.
Scroll down to the web hosting section.
Select the relevant domain name from the drop down box and click on the Manage button.
Click on the Perl & PHP Module List option in the Website Help & Diagnostics section.
Here you will see a list of the modules available in your hosting account.