I would recommend a slight change on the above advice. Instead of wasting the server resource to tar up your files and untar them once they're here at DH, just use FTP (or SFTP) from the DH server to transfer over your files.
First you'll need to make sure that the user who controls your domain here at DH has ssh access. To do this log into the Panel > Users > Manage Users. click edit across from the user in questoion and then place a check mark to allow ssh (shell) access.
That change will take a few min. to take effect. In the mean time you'll need a program such as putty to log into the server with. Run putty and log into your domain, using the user/pass you just gave rights to.
first lets move into your website directory. Use the command "cd" to change directory -
next use the program ftp or sftp (which ever you prefer of your old host accepts) that command will look something like
press enter and you should be prompted for your password. the "cd" command will work here to change directory on the remote server. "ls" will list the files in your current directory, and "get" and "mget" will retrieve a single file and multiple files respectively.
I hope this makes sense, let me know if you need more explanation or if you have problems.
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