The mib looks good and I get the same 'no such object' when I test with it - which makes sense since I don't have an actual netapp device. Can you confirm that your device should be responding to requests to walk this OID? What does the output look like if you run:
The walk does not return the expected OID. At this point I would turn my attention to the netapp device - it doesn't appear that the OID exists on the device.
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