Solved it marshalljohns. The key to the error is the “Permission denied in” part. It’s a problem with the files being ‘locked’ on your hosts server. The new installation can’t overwrite the old files so for some reason everything gets buggered.
Go to your WordPress install on your hosts server. Find the offensive file, in this case the thickbox.js. Right click on it and go to permissions. Make sure the permission is set to 777, that will basically ‘unlock’ it. Try the install again.
