To get rid of the errors activate atleast

Common HTTP Features
Static Content
Default Document
HTTP Redirection
Directory Browsing

Application Development
ASP.Net
ISAPI Extension
ISAPI Filters

Security
Windows Authentication

Management Tools
IIS Metabase
IIS 6 WMI

I however activated all and removed the ones I did not want after install.

And you have to run this command to make x64 IIS accept 32bit applications such as reporting services.

cscript %SystemDrive%\inetpub\AdminScripts\adsutil.vbs set w3svc/AppP
ools/Enable32bitAppOnWin64 1

Fetched from
http://www.jameskovacs.com/blog/ReportingServicesOnWindowsVista.aspx
and
http://www.tryexcept.com/articles/2007/07/18/installing-sql-server-2005-express-in-windows-vista.html