SilverStripe Complains about Friendly URLs

I've just installed SilverStripe from the Control Panel. It complains that friendly URLs aren't enabled:

> Friendly URLs are not working. This is most likely because a rewrite module
> isn't configured correctly on your site. You may need to get your web host or
> server administrator to do this for you:
> - mod_rewrite or other rewrite module is enabled on your web server
> - AllowOverride All is set for the directory where SilverStripe is installed

Does anyone know what to do with this advice? I've connected to the site through IIS, but I don't think these instructions are for IIS.

Thanks.

 

Thanks for your response. What I put in my post is the actual error message.