IIS7 has been made alive with Windows Vista (full server release will be with Windows Server 2008) and offers many new features. You can read about them at www.iis.net. One of the most exciting features was option to extend IIS using ASP.NET and managed code or so called to "plug into integrated pipeline mode".
So far I was able to run ASP.NET sites using application Classic .NET App Pool. But so far I wasn't able to utilize Integrated pipeline mode.
By setting Managed pipeline mode to Integrated causes my app stop working with terrible error.
Although the message in event log I wasn't able to find a solution although good message:
A request mapped to aspnet_isapi.dll was made within an application pool running in Integrated .NET mode. Aspnet_isapi.dll can only be used when running in Classic .NET mode. Please either specify preCondition="ISAPImode" on the handler mapping to make it run only in application pools running in Classic .NET mode, or move the application to another application pool running in Classic .NET mode in order to use this handler mapping.
Well... the error is in aspnet_isapi.dll. So let's remove ISAPI related modules from modules section
After this operation I got Error 500
HTTP Error 500.0 - Internal Server Error
Description: Handler "AboMapperCustom-76525" has a bad module "IsapiModule" in its module list
So the next step is to remove all Handler Mappings that are mapped to IsapiFilter
And ... voila.. this was it...
Hope you'll find this helpful.