Moving media library to a new server not showing up

I have multisite setup on an old server and a new server. I'm moving individual blogs from the old server to the new one. When I imported blog posts, it didn't pull in all of the old media, so I FTP'd into both servers and transferred from the blogs.dir directory all of the items from the old blog to the new blog. However, the media doesn't show up on the new server in the media library within WordPress. Any suggestions as to what I'm doing wrong here?