ASP.Net Error: "The requested content appears to be script and will not be served by the static file handler"

This means that, while there exist a handler that maps to that type of content (e.g. aspx), it doesn't apply to currently used .NET Framework.
Solution is to run aspnet_regiis.exe -i for the current framework. (e.g. C:\Windows\Microsoft.NET\Framework\v4.0.30319\aspnet_regiis.exe -i)
If that doesn't work, then double check whether there's a handler that maps to that content for integrated pipeline mode. If there's not, a possible solution is to change to classic pipeline mode.