local profile to domain profile: error

problem: i have some computers that were once in a simple workgroup but i have decided to move them to a domain. the problem is that the users seem to lose all of their profile information once they log into the domain. i have been searching and searching past questions to hopefully find a solution to my problem. fortunately i found a number of different solutions. the best solution according to the community is as follows:

“Log on as Administrator on the ‘local’ machine. From the Advanced Tab of System Properties, click on the Settings button for profiles, after having logged on as the new domain user and given that user admin privledges to the local machine. Find the listing for the old “local” user profile that you want to retain, then click the copy button and browse under the Document& Settings folder to the new “ and copy the profile. After setting user back to whatever security level you want them to have, log back in as that domain user.”

unfortunately this does not work for me because during this process i get the following error:

Profile Error
Directory coulld not be deleted. Please delete the directory and retry.

i can’t seem to be able to delete the directory because it contains the NTUSER.dat files that won’t delete because they are “in use”.

what can i do?