.net client connectivity

i was trying out a sample CB client code that was working well a couple of days back (i had to look at other parts ). suddenly the store calls are returning false indicating the object was not saved. the code is as below. How can i trouble shoot the issue ?

var newBeer =
@"{
""name"": ""Old Yankee Ale"",
""abv"": 5.00,
""ibu"": 0,
""srm"": 0,
""upc"": 0,
""type"": ""beer"",
""brewery_id"": ""110a45622a"",
""updated"": ""2012-08-30 20:00:20"",
""description"": ""A medium-bodied Amber Ale"",
""style"": ""American-Style Amber"",
""category"": ""North American Ale""
}";

var config = new CouchbaseClientConfiguration();
config.Urls.Add(new Uri("http://localhost:8091/pools/"));
config.Bucket = "default";

log.Debug("Created Config to connect to default bucket.");

var client = new CouchbaseClient(config);

ServerStats _stats = client.Stats();

var key = BitConverter.ToString(HashAlgorithm.Create("SHA1")
.ComputeHash(Encoding.UTF8.GetBytes(newBeer)))
.Replace("-", "").Substring(0, 10).ToLower();

var result = client.Store(StoreMode.Add, key, newBeer);