Client-side error-report: Uncaught ReferenceError: check_url is not defined

On logging onto the Admin Web console.

Client-side error-report for user "Administrator" on node 'ns_1@10.3.121.13':
User-Agent:Mozilla/5.0 (Macintosh; Intel Mac OS X 10_7_4) AppleWebKit/537.1 (KHTML, like Gecko) Chrome/21.0.1180.79 Safari/537.1
Got unhandled error: Uncaught ReferenceError: check_url is not defined
At: :1
Backtrace:
Function: collectBacktraceViaCaller
Args:

---------
Function: appOnError
Args:
"Uncaught ReferenceError: check_url is not defined"
""
1
---------

Client-side error-report for user "Administrator" on node 'ns_1@10.3.121.13':
User-Agent:Mozilla/5.0 (Macintosh; Intel Mac OS X 10_7_4) AppleWebKit/537.1 (KHTML, like Gecko) Chrome/21.0.1180.79 Safari/537.1
Browser client XHR failure encountered. (age: 15997771) Diagnostic info:
s: {"url":"/pools/default/buckets/default/localRandomKey?_=1345519976847","isLocal":false,"global":true,"type":"GET","contentType":"application/json","processData":true,"async":true,"accepts":

{"xml":"application/xml, text/xml","html":"text/html","text":"text/plain","json":"application/json, text/javascript","*":"*/*","script":"text/javascript, application/javascript, application/ecmascript, application/x-ecmascript"}

,"contents":{"xml":{},"html":{},"json":{},"script":{}},"responseFields":

{"xml":"responseXML","text":"responseText"}

,"converters":

{"text html":true}

,"jsonp":"callback","timeout":30000,"cache":false,"dataType":"json","dataTypes":["text","json"],"crossDomain":false,"hasContent":false}
xhrStatus: error,
xhrReadyState: 0,
errMsg: ,
statusCode: 0,
responseText:

From Chrome logs
Object
album: ""
album_art: "http://undefined"
artist: ""
current_time: ""
now_playing: function () {
arguments: null
caller: null
length: 0
name: ""
prototype: Object
_proto_: function Empty() {}
song_title: ""
status: undefined
total_time: ""
_proto_: Object
_defineGetter: function __defineGetter_()

{ [native code] }
_defineSetter: function __defineSetter_() { [native code] }

_lookupGetter: function __lookupGetter_()

{ [native code] }
_lookupSetter: function __lookupSetter_() { [native code] }

constructor: function Object()

{ [native code] }
hasOwnProperty: function hasOwnProperty() { [native code] }

isPrototypeOf: function isPrototypeOf()

{ [native code] }
propertyIsEnumerable: function propertyIsEnumerable() { [native code] }

toLocaleString: function toLocaleString()

{ [native code] }
toString: function toString() { [native code] }

valueOf: function valueOf()

{ [native code] }