Unable to upload files on Redmine installed on a Windows IIS server

The following instructions were used to install Redmine on a Windows server:
http://www.helicontech.com/articles/installing-redmine-on-windows-in-production/

Problem:
There is an error when you try to upload files to a project in Redmine.

Solution:

1. Create a folder in the root of the Redmine installation directory:
   C:\inetpub\wwwroot\redmine\files
2. Add write permission to this directory.  In our case we had a IIS_IUSRS user that was given modify permission for this directory.

References:

• http://www.redmine.org/boards/2/topics/12086