I have just installed Omeka for the first time and ran into some issues. My web host able to resolve the main issue (converted your htaccess file to a web.config to do IIS rewrite instead due to the mod rewrite rules had some incompatibilities with Isapi_Rewrite).
Before I could access the site but not the admin. Now I can access the admin but I see a 404 inside the admin and looks as if no CSS is loading.
http://gastonlibrary.org/omeka/ is the site.
It looks like your host may have been a little overinclusive in trying to translate our .htaccess to IIS.
The rewrite on your site seems to be applying to all URLs, where Omeka's normal one doesn't apply to any files that exist on the filesystem. Basically, your server seems to be trying to route all the requests to things like .css and .js files through Omeka's PHP code, which shouldn't be happening.
Thanks, I will share this with the host.
hi i have a problem converting the .htaccess to web.config. is it possible to share your web.config ?