Yes, our new (www.domain.com) address leads to the SAME place as our old (www.host.com/domain) address! We haven't changed hosts.
No problem with google and very few problem with Inktomi since we have several paid registered pages.
The only problem concerns Altavista. Our main page was ranking to the top for targeted keywords (without spamming or using tricks) because there are a lot of themed sites linking to us.
Maybe Altavista is not so stable in these days: we noticed that we have pages ranking fine for same targeted keywords, only because we have those keywords in the "keyword metatag"; this applies for keywords in capital letters for example.
What it is curious that this apply mainly for the main page. Most of new dominion page are listed fine. Doing a search on Altavista using the feature "More page from this site" related to the old dominion shows me two times (two listings) the main old dominion pages: the page of few months ago and the page with slight modifications of few weeks ago.
I have the impression that Altavista is using different databases because sometimes I can find both the new and the old dominion, sometimes only the new one, sometimes only the old one.