500 Internal Server Error when setting up Apache on localhost

Question

I downloaded and installed XAMPP, and to keep my projects nicely separated I want to create a VirtualHost for each one based on its future domain name. For example, in my first project (we'll say it's project.com) I've put this in my Apache configuration:

NameVirtualHost 127.0.0.1

<VirtualHost 127.0.0.1:80>
DocumentRoot C:/xampp/htdocs/
ServerName localhost
ServerAdmin admin@localhost
</VirtualHost>

<VirtualHost 127.0.0.1:80>
DocumentRoot C:/xampp/htdocs/sub/
ServerName sub.project.com
ServerAdmin [email protected]
</VirtualHost>

<VirtualHost 127.0.0.1:80>
DocumentRoot C:/xampp/htdocs/project/
ServerName project.com
ServerAdmin [email protected]
</VirtualHost>

And this in my hosts file:

# development
127.0.0.1 localhost
127.0.0.1 project.org
127.0.0.1 sub.project.org

When I go to project.com in my browser, the project loads up successfully. Same if I go to sub.project.com. But, if I navigate to: http://project.com/register (one of my site pages) I get this error:

Internal Server Error

The server encountered an internal error or misconfiguration and was
unable to complete your request.

The error log shows this:

[Sun May 20 02:05:54 2012] [error] [client 127.0.0.1] Request exceeded
the limit of 10 internal redirects due to probable configuration
error. Use 'LimitInternalRecursion' to increase the limit if
necessary. Use 'LogLevel debug' to get a backtrace., referer:
http://project.com/

Sun May 20 02:05:54 2012] [error] [client
127.0.0.1] Request exceeded the limit of 10 internal redirects due to probable configuration error. Use 'LimitInternalRecursion' to increase
the limit if necessary. Use 'LogLevel debug' to get a backtrace.,
referer: http://project.com/

Any idea what config items I got wrong or how to get this working? It happens on any page that's not in in the root directory of project.com. Thanks.

Solution

As the error message indicates, you have a bad RewriteCond/RewriteRule redirect in the .htaccess file of the root folder, DocRoot folder, or one of the sub-folders.

It's looping on itself and after 10 internal redirects, Apache is killing it to protect the process.