Expression Engine - Access Forbidden Issues

Whenever I have create a new template group开发者_Python百科 in EE I can access that template group's index file as follows:

http://www.mysite.com/my_template_group/

However, I am working on a project and for the first time ever if I use that link I get the following error message:

You do not have permission to access this directory.

If I include the index in the url it works fine:

http://www.mysite.com/my_template_group/index

What would be causing this snafu and how can I resolve it? Using the /index in the link is unacceptable.

Thanks.

You don't just happen to have an empty folder in your site root with the same name as your template group?