Hi and thanks for thins extension!

I'm trying to install a trial version I received from your support service on my Joomla 1.5 website.

The installation is ok, as I get the standard confirmation message shown on your pdf documentation. But, once I click the link to access the Responsivizer admin panel, I get the following error message:

Code:

Fatal error: Call to undefined function json_decode() in /mnt/116/sdb/a/4/stefanstennis/administrator/components/com_responsivizer/framework/registry/format/json.php on line 45

This is the phpinfo of my website, which is built on a free.fr with mysql enabled. Is there a solution to this problem or does it mean I can't install your extension on my server? Thank you!