Omeka installation problem

Hello,
I just installed omeka 2.3 for a new website, I was used to 2.0.2.
After following installation steps, I could not launch installation by visiting http://mydomain.org/project, which returned an internal server error. I did manage the installation by viting http://mydomain.org/project/install/install.php.
But now to access every location of my omeka site (admin panel, index, items, simple pages...), I need to add "index.php" in the url (if I don't I still get the internal servor error).
For instance to access the admin panel:
http://mydomain.org/project/admin/index.php
To access an item:
http://mydomain.org/project/index.php/items/show/itemnumber
And to access the "about" simple page:
http://mydomain.org/project/index.php/about

This workaround is not very efficient, because I would need to apply it everywhere in the code of omeka...

Has anyone already encountered this issue? If so, how did you manage to solve it?

Thanks,
François.

My first guess is that something is amiss with the .htaccess file. Maybe double-check that the new file for 2.3 was uploaded along with the rest of the files.

Thanks for the quick reply.
I checked and the .htaccess file has been correctly uploaded. Do I need to change something in it?

Hello, I still have the same problem. Any idea how to solve it?
Thanks.

Usually not. From what I can tell, it looks like the rewrite rule RewriteRule .* index.php is not being applied correctly.

What OS / version and version of Apache are you running?