domain not found

Ok, so i've installed the component, been through the configuration guid and tried to access my site from my iphone. However I get the error message that the domain iphone.salcombewebdesign.com cannot be found.

If I try to access the mobile version from my desktop computer I get a 404 component not found error message and the URL changes to www.salcombewebdesign.com/mobile-version (rather than for example iphone.salcombewebdesign.com.

I've tried switching off SEF URL's in the joomla global configuration, but this has no effect. Has anyone experienced this same issue? What am I missing? As far as I can tell the component isn't being found for some reason.

Help please!

When I try to go to www.salcombewebdesign.com on my iphone, it is being redirected to iphone.salcombewebdesign.com, and next message is displayed.
"The iphone version of this website is on it's way. Salcombe Web Design has gone mobile."