The easy solution is to give the host instance service account full control NTFS rights. But some companies have a policy against using full control NTFS rights. Giving full control is not strictly necessary. Just ‘modify plus’ rights will do: http://blogs.msdn.com/b/sanket/archive/2009/06/06/required-ntfs-permissions-for-biztalk-file-adapter-connecting-to-network-share.aspx
