I have follwed the guides to the letter.. it just doesn't work. I have also tried everything on the page you linked to, and tried disabling all other modules.
Unfortunately runAllManagedModulesForAllRequests="true" causes png images not to be sent to the browser.. it's a bug in DNN 5.6.0 as far as I can tell.
I just had a look at the source code on codeplex.. there's been some checkin's recently for the URLRewrite module which is where the issue seems come from. I downloaded and built from the source and it did resolve the png issue, with the vanity url's working fine, however it broke downloads from our website . This is what I see now :
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DotNetNuke Error
Domain Name Windows Vista Does Not Exist In The Database
DotNetNuke supports multiple portals from a single database/codebase. It accomplishes this by converting the URL of the client browser Request to a valid PortalID in the Portals database table. The following steps describe the process:
1. Web Server Processing
* When a web server receives a Request from a client browser, it compares the file name extension on the target URL resource to its Application Extension Mappings defined in IIS.
* Based on the corresponding match, IIS then sends the Request to the defined Executable Path ( aspnet_asapi.dll in the case of ASP.NET Requests ).
* The aspnet_isapi.dll engine processes the Request in an ordered series of events beginning with Application_BeginRequest.
2. HttpModule.URLRewrite OnBeginRequest ( UrlRewriteModule.vb )
* The Request URL is parsed based on the "/" character
* A Domain Name is constructed using each of the relevant parsed URL segments.
Examples:
URL:
http://www.domain.com/default.aspx = Domain Name: www.domain.com
URL:
http://209.75.24.131/default.aspx = Domain Name: 209.75.24.131
URL:
http://localhost/DotNetNuke/default.aspx" target="_blank" rel="nofollow">
http://localhost/DotNetNuke/default.aspx = Domain Name: localhost/DotNetNuke
URL:
http://www.domain.com/virtualdirect...fault.aspx = Domain Name: www.domain.com/virtualdirectory
URL:
http://www.domain.com/directory/default.aspx = Domain Name: www.domain.com/directory
* Using the Domain Name, the application queries the database ( Portals table - PortalAlias field ) to locate a matching record.
Note: If there are multiple URLs which correspond to the same portal then the PortalAlias field must contain each valid Domain Name in a comma seperated list.
Example:
URL:
http://localhost/DotNetNuke/default.aspx" target="_blank" rel="nofollow">
http://localhost/DotNetNuke/default.aspx URL: http://MACHINENAME/DotNetNuke/default.aspx
URL: http://209.32.134.65/DotNetNuke/default.aspx
PortalAlias: localhost/DotNetNuke,MACHINENAME/DotNetNuke,209.32.134.65/DotNetNuke
Note: If you are installing the application to a remote server you must modify the PortalAlias field value for the default record in the Portals table according to the rules defined above.
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that was when attempting to download a file from a virtual directory e.g :
http://www.mydomain.com/downloads/product/700/dodah.exe
downloads is configured as a virtual directory in IIS7. It seems DNN5.6 is seriously broken.