healthchecker launches exceptions when reading data

root@cola-s10302:/opt/couchbase/bin# ./cbhealthchecker -c localhost:8091 -u Administrator -p password
ERROR: unable to bucket-ddocs; please check your username (-u) and password (-p); (404) Object Not Found Traceback (most recent call last):
File "/opt/couchbase/lib/python/collector.py", line 169, in number_bucketddocs
docs = buckets.Buckets().runCmd('bucket-ddocs', server, port, user, password, opts_tmp)
File "/opt/couchbase/lib/python/timeout.py", line 67, in wrapper
return function(*args, **kargs)
File "/opt/couchbase/lib/python/buckets.py", line 162, in runCmd
self.user, self.password, opts)
File "/opt/couchbase/lib/python/restclient.py", line 162, in restCmd
return self.handleResponse(method, response, opts)
File "/opt/couchbase/lib/python/restclient.py", line 70, in handleResponse
output_json = json.loads(response.read())
File "/opt/couchbase/lib/python/simplejson/_init_.py", line 307, in loads
return _default_decoder.decode(s)
File "/opt/couchbase/lib/python/simplejson/decoder.py", line 335, in decode
obj, end = self.raw_decode(s, idx=_w(s, 0).end())
File "/opt/couchbase/lib/python/simplejson/decoder.py", line 353, in raw_decode
raise ValueError("No JSON object could be decoded")
ValueError: No JSON object could be decoded