Sometimes when you move a site the file system permissions below /Data can get funky and you may need to reset permissions on files and folders so the new applicaiton pool user has permissions. And of course make sure all of the files were copied successfully for the other sites under /Data/Sites/[SiteID]
Check the log for errors, if the log doesn''t have nay new entries it definitely indiicates file system permission problems because tha means it also cannot write to the log. But the blank skin sounds more like incorrect read permissions on the skin folder files.
Hope that helps,