Must type "www" in internet explorer

I created a Flash (mx 2004 pro) web page and embedded it into an html document. The problem is a client (using Internet Explorer- not the latest version) can’t see the page unless they type “www.webpagename.com” into the address bar at the top. If they type just the name “webpagename” or “webpagename.com” in the address bar (as most people are accustomed to these days) the browser plays dumb and defaults to a google search.
It’s only happened since I uploaded the the new Flash page embedded in the html. Maybe there’s something missing from the html script?
Does it have anything to do with the fact the “index” page is rerouted to “index_content” as a default in the Flash publishing settings?

-I browsed through a few pages on this forum looking for the topic but didn’t see anything that immediately popped into view, so if this has been covered before I apologize.
Thanks-
Erik