403 forbidden error when trying to access admin

I just installed the newest version of Zen cart and I am getting this error:
403 forbidden
Server configuration does not allow access to this page. Please go back and try again.

when trying to log into the admin section of my site. I contacted ipower (my host) and they say everything is fine on there end. When you go to my site, the cart is there, but I can't get into the admin section

http://simplyjdesigns.com/catalog/

any suggestions?

Thank you,
Jackie

I fixed my permissions which were incorrect, but now I am getting this error when trying to access the admin portion of my site:

Warning: require(includes/functions/html_output.php) [function.require]: failed to open stream: Permission denied in /home/simplyjd/public_html/catalog/admin/includes/init_includes/init_general_funcs.php on line 33

Fatal error: require() [function.require]: Failed opening required 'includes/functions/html_output.php' (include_path='.:/usr/local/lib/php') in /home/simplyjd/public_html/catalog/admin/includes/init_includes/init_general_funcs.php on line 33

What does this need to be fixed?

Thank you.