I was searching for some help on this error for days. Tried adding different mappings. Then I found this page :
http://www.sven-s.de/post/BlogEngine-HTTP-4043-cshtml-Handler-not-registered-in-Shared-Hosting.aspx
“
HTTP Error 404.3 – Not Found
The page you are requesting cannot be served because of the extension configuration. If the page is a script, add a handler. If the file should be downloaded, add a MIME map.
The solution is, to add the following handlers to web.config:
<system.webServer>
<handlers>
<add name="cshtml-ISAPI-4.0_32bit" path="*.cshtml" verb="GET,HEAD,POST,DEBUG"
modules="IsapiModule"
scriptProcessor="C:\Windows\Microsoft.NET\Framework\v4.0.30319\aspnet_isapi.dll"
preCondition="classicMode,runtimeVersionv4.0,bitness32" responseBufferLimit="0" />
<add name="cshtml-ISAPI-4.0_64bit" path="*.cshtml" verb="GET,HEAD,POST,DEBUG"
modules="IsapiModule"
scriptProcessor="C:\Windows\Microsoft.NET\Framework64\v4.0.30319\aspnet_isapi.dll"
preCondition="classicMode,runtimeVersionv4.0,bitness64" responseBufferLimit="0" />
<add name="cshtml-Integrated-4.0" path="*.cshtml" verb="GET,HEAD,POST,DEBUG"
type="System.Web.HttpForbiddenHandler"
preCondition="integratedMode,runtimeVersionv4.0" />
</handlers>
</system.webServer>
“
Added this settings to the web.config file in the admin folder and “Wham bam thank you…….”. Now it it works.
Atle