I'm testing this free blog extension for v 2.0.3.1:
http://www.opencart.com/index.php?route ... _license=0
The instalation goes smoothly, everything shows up in the modifications list, but when I try to access the modules I receive a "Permit Denied" and a message to contact my web admin for permission... which is me

This has happened with other blogs I've tried, so I suspect is a problem in my end, not the extensions.
I have a basic knowledge of HTML and I've already made some succesfull changes to my site, I suspect this might have something to do with file permssions (I might be wrong, of course), but before starting poking around I would like to know if anyone has knowledge on how to solve this, or at least point me out in the right direction.
Thank you in advance for your help!