The following code should be added in the web.config:
<system.webServer>
<validation validateIntegratedModeConfiguration="false" />
<handlers>
//...
<add name="MiniProfiler" path="mini-profiler-resources/*" verb="*" type="System.Web.Routing.UrlRoutingModule" resourceType="Unspecified" preCondition="integratedMode" />
</handlers>
</system.webServer>