Francesco,
When you say you are having the same problem with a W2k8R2 server as well as your NetApp storage, did you restart your connector, reset the thinapp repo on the connector-va and then add the windows share? I'm having the same problems in CIFS from NetApp, and after attempting to activate the share, it fails, but when I enter a new W2K8R2 share it also fails until I restart the connector-va. After the reboot, the Windows share is fine. If I try to change it to the NetApp CIFS share, then I again get the ERROR_NETNAME_DELETED.
I'm not sure if this is related, but our IT department was trouble shooting some other CIFS issues with a remote branch and wireshark packet captures show that for every file request on the NetApp CIFS share three attempts are made and fail, then the 4 succeeds. Unfortunately I'm unable to try and reproduce this at this time - everyone seems to be on vacation. I suspect it might be the culprit. I'll try and get a more verbose log level from the connector-va and post back.