NDMP restore is not allowed across different NAS vendors. This is due to the fact each vendor implements NDMP protocol differently at their end. Even though NDMP is a open-standard protocol, it's just a NAS Management (transport) protocol. NAS vendors are free to implement their backup format (ex- emc=tar,netapp=ufs_dump). In short - The source and destination must be of the same NAS vendor type.
To transfer data : I am afraid, you will need to copy data at file-system protocol layer (CIFS/NFS/NTFS/etc) between the two vendors.