You can ask for help on the issues board -
https://bitbucket.org/yetanotherchris/roadkill/issues?status=new&status=open
However I can tell you that the problem is most likely that you don't have MVC installed on IIS (if it's Windows Server 2008). You might also need to enable ISAPI filters, they can be turned off.
The ASP.NET web installer contains the MVC bits you need, although Roadkill does come bundled with these.