HttpClientRequest error on device but not in emulator

I am having a problem while try to authentication by HttpClientRequest on android device. But it is working in emulator and also works with iPhone. i can't identify where my problem is in. Please help me out. Below is my error log file information.

-- Start application log -----------------------------------------------------
[INFO] :   TiApplication: (main) [0,0] checkpoint, app created.
[INFO] :   TiApplication: (main) [112,112] Titanium 3.2.0 (2013/12/20 10:57 d9182d6)
[INFO] :   I/dalvikvm-heap: Grow heap (frag case) to 12.981MB for 486820-byte allocation
[INFO] :   I/dalvikvm-heap: Grow heap (frag case) to 13.674MB for 243418-byte allocation
[INFO] :   TiApplication: (main) [576,688] Titanium Javascript runtime: v8
[INFO] :   TiRootActivity: (main) [0,0] checkpoint, on root activity create, savedInstanceState: null
[WARN] :   V8Object: Runtime disposed, cannot set property 'userAgent'
[INFO] :   I/dalvikvm-heap: Grow heap (frag case) to 13.996MB for 614416-byte allocation
[INFO] :   I/dalvikvm-heap: Grow heap (frag case) to 16.337MB for 2457616-byte allocation
[INFO] :   TiRootActivity: (main) [0,0] checkpoint, on root activity resume. activity = com.horsecount.app.HorsecountActivity@42619d90
[INFO] :   Choreographer: Skipped 125 frames!  The application may be doing too much work on its main thread.
[ERROR] :  SensorManager: thread start
[INFO] :   Choreographer: Skipped 31 frames!  The application may be doing too much work on its main thread.
[INFO] :   Sensors: sendDelay --- 200000000
[INFO] :   SensorManager: Set normal delay = true
[ERROR] :  V8Exception: Exception occurred at undefined:1: Uncaught SyntaxError: Unexpected token <
[ERROR] :  XMLModule: (KrollRuntimeThread) [11753,11753] Error parsing XML
[ERROR] :  XMLModule: org.xml.sax.SAXParseException: attr value delimiter missing! (position:START_TAG <meta http-equiv='urn:schemas-microsoft-com:vml'>@8:18 in java.io.InputStreamReader@427817b0)
[ERROR] :  XMLModule:   at org.apache.harmony.xml.parsers.DocumentBuilderImpl.parse(DocumentBuilderImpl.java:146)
[ERROR] :  XMLModule:   at javax.xml.parsers.DocumentBuilder.parse(DocumentBuilder.java:107)
[ERROR] :  XMLModule:   at ti.modules.titanium.xml.XMLModule.parse(XMLModule.java:82)
[ERROR] :  XMLModule:   at ti.modules.titanium.network.TiHTTPClient.getResponseXML(TiHTTPClient.java:661)
[ERROR] :  XMLModule:   at ti.modules.titanium.network.HTTPClientProxy.getResponseXML(HTTPClientProxy.java:93)
[ERROR] :  XMLModule:   at org.appcelerator.kroll.runtime.v8.V8Object.nativeCallProperty(Native Method)
[ERROR] :  XMLModule:   at org.appcelerator.kroll.runtime.v8.V8Object.callProperty(V8Object.java:69)
[ERROR] :  XMLModule:   at org.appcelerator.kroll.KrollProxy.handleMessage(KrollProxy.java:1121)
[ERROR] :  XMLModule:   at android.os.Handler.dispatchMessage(Handler.java:95)
[ERROR] :  XMLModule:   at android.os.Looper.loop(Looper.java:137)
[ERROR] :  XMLModule:   at org.appcelerator.kroll.KrollRuntime$KrollRuntimeThread.run(KrollRuntime.java:112)
[ERROR] :  TiHttpClient: (KrollRuntimeThread) [14,11767] Error parsing XML
[ERROR] :  TiHttpClient: org.xml.sax.SAXParseException: attr value delimiter missing! (position:START_TAG <meta http-equiv='urn:schemas-microsoft-com:vml'>@8:18 in java.io.InputStreamReader@427817b0)
[ERROR] :  TiHttpClient:    at org.apache.harmony.xml.parsers.DocumentBuilderImpl.parse(DocumentBuilderImpl.java:146)
[ERROR] :  TiHttpClient:    at javax.xml.parsers.DocumentBuilder.parse(DocumentBuilder.java:107)
[ERROR] :  TiHttpClient:    at ti.modules.titanium.xml.XMLModule.parse(XMLModule.java:82)
[ERROR] :  TiHttpClient:    at ti.modules.titanium.network.TiHTTPClient.getResponseXML(TiHTTPClient.java:661)
[ERROR] :  TiHttpClient:    at ti.modules.titanium.network.HTTPClientProxy.getResponseXML(HTTPClientProxy.java:93)
[ERROR] :  TiHttpClient:    at org.appcelerator.kroll.runtime.v8.V8Object.nativeCallProperty(Native Method)
[ERROR] :  TiHttpClient:    at org.appcelerator.kroll.runtime.v8.V8Object.callProperty(V8Object.java:69)
[ERROR] :  TiHttpClient:    at org.appcelerator.kroll.KrollProxy.handleMessage(KrollProxy.java:1121)
[ERROR] :  TiHttpClient:    at android.os.Handler.dispatchMessage(Handler.java:95)
[ERROR] :  TiHttpClient:    at android.os.Looper.loop(Looper.java:137)
[ERROR] :  TiHttpClient:    at org.appcelerator.kroll.KrollRuntime$KrollRuntimeThread.run(KrollRuntime.java:112)

function auth_token(_username, _password, _loginUrl, onComplete) {
 
    var xhr = Titanium.Network.createHTTPClient({
 
        onload : function(e) {
            json = JSON.parse(this.responseText);
            var token = json.auth_token;
            onComplete(token);
        },
 
        onerror : function(e) {
             Ti.API.info("STATUS: " + this.status);
             Ti.API.info("TEXT:   " + this.responseText);
             Ti.API.info("ERROR:  " + e.error);
        },
        timeout : 5000
    });
 
    xhr.open("POST", _loginUrl);//xhr.open("POST", _loginUrl, false);
    xhr.setRequestHeader("Content-type", "application/json; charset=utf-8");
    data_to_send = {
        username : _username,
        password : _password
    };
 
    xhr.send(JSON.stringify({
        prop : 'string',
        user : data_to_send
    }));
 
}
 
module.exports = auth_token;