You are doing that from inside Windows, right? And if you are doing it from Vista - I strongly advise not to do it; there have been problems with that and Vista. Boot from the DVD instead.
No, bcdedit is correct. And you got lucky - probably it did not run because your Vista user does not have adequate privilege, or because of how you have UAC configured. In any case, again, please do NOT start the install from inside Vista this way. And don’t touch bcdedit unless you really know what you are doing.