We have just installed Silverstripe, right now, we are able to view and navigate thru the entire website - so I assume that mod_rewrite is working properly. However, when we try to login through the admin interface, we just get redirected back to the login page, with a message saying "You're logged in as Admin." We are unable to access the CMS itself, as we keep getting directed back to the login page after a successful login.

Here are the contents of the .htaccess file:

### SILVERSTRIPE START ###
RewriteEngine On
RewriteBase /

RewriteCond %{REQUEST_URI} !(\.gif)|(\.jpg)|(\.png)|(\.css)|(\.js)|(\.php)$

RewriteCond %{REQUEST_URI} ^(.*)$
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule .* sapphire/main.php?url=%1&%{QUERY_STRING} [L]
### SILVERSTRIPE END ###

Any idea what the problem may be?

I hear your pain.

I installed a week or so back and encountered a similar problem. When you installed you were given the option of using a user name or an email address as your preferred login method. I tried the user name option but then could not subsequently log in. I reinstalled using the email address option and have had no further problems. Worth a try?