Drupal for Firebug not working on hosted site

Issue Summary

Hello,

First, here is my setup:

Firefox 3.6.12 with activated additional modules: Firebug 1.5.4 and DrupalForFirebug 0.0.7
Drupal 6.19 with activated modules:
• Devel 6.x-1.22
• Drupal for Firebug 6.x-1.3
• Drupal for Firebug Preprocessor 6.x-1.3

1 – Site on my LAMP server (mysql 5.1.37, php 5.2.10) = Works fine; I see Drupal for Firebug infos
2 – Site at FreeHeberg.com (mysql 5.0.44, php 5.2.5) = "No Drupal for Firebug data was found. Either this site is not running Drupal or the Drupal for Firebug module has not been installed/enabled."

Note: I have already fully reinstalled site n°2 with no better luck.

Can you see something I forgot to setup on my hosted site at FreeHeberg.com?

Thanks for your help