I installed the alpha without difficulty, but now I don't seem to be able to install the official release. I checked that the .htaccess files are there - but still can't access my /admin directory. The root directory is fine.
You can see it here:
http://kerim.joyeurs.com/omeka/
All the links work, but this gives a 500 error:
http://kerim.joyeurs.com/omeka/admin/
Thanks!
kerim