Probably the most frequent SSLRedirect installation problem is the fact that one's SSL Certificate is not properly installed beforehand.  I truly believe in a "process of elimination" when it comes to problem isolation, so I would suggest that the easiest thing to do to verify one's SSL Certificate installation is to first create a native HTML Hello World web page (HelloWorld.html).   Once created and one is sure that the SSL Certficate has been installed properly and the web site bindings are properly defined within IIS (port 80 for HTTP traffic and usually port 443 for HTTPS traffic), then simply try invoking the HelloWorld.html web page to ensure its usage with both HTTP and HTTPS.  Use of the simple HelloWorld.html web page will bypass SSLRedirect and any content management system, such as DotNetNuke.  If the HelloWorld.html web page works properly with both HTTP and HTTPs then you are set to try SSLRedirect with your real world web site environment.