Is there something that can be turned on on the netapp side to get more details about what the filer is doing, name-lookup-wise?
Not that I can think of offhand (although a future filer release will have somewhat more detailed error messages), but a network trace might help (if I remember correctly, the problem that inspired the more detailed error messages is that a variety of errors get reported as "Connection timed out", including some where the DNS server *did* respond but sent back an error).