Android Question reading from database i get internal servel error

#Region  Activity Attributes
    #FullScreen: False
    #IncludeTitle: True
#End Region

Sub Process_Globals
    'These global variables will be declared once when the application starts.
    'These variables can be accessed from all modules.
    Dim strUserID As String
    Dim strUserName As String

End Sub

Sub Globals
    'These global variables will be redeclared each time the activity is created.
    'These variables can only be accessed from this module.
    Private ListView1 As ListView
    Private btnLogout As Button
    Private lblMessage As Label
       Private lblMessage As Label

End Sub

Sub Activity_Create(FirstTime As Boolean)
    'Do not forget to load the layout file created with the visual designer. For example:
    'Activity.LoadLayout("Layout1")
    Dim readtbl As HttpJob

    Activity.LoadLayout("frmtrackead")
    lblMessage.Text = "Welcome, " & Login.strUserName
    'ToastMessageShow(currentURL, False)

    readtbl.Initialize("readtbl", Me)
    readtbl.Download2("http://www.myweserver.com/readtracktbl.php", _
    Array As String("user_id", Login.strUserID))
    ProgressDialogShow("Connecting to server...")

End Sub

Sub Activity_Resume

End Sub

Sub Activity_Pause (UserClosed As Boolean)

End Sub

Sub JobDone (Job As HttpJob)
    ProgressDialogHide
    If Job.Success = True Then
        Dim strReturn As String = Job.GetString
        Dim parser As JSONParser
        parser.Initialize(strReturn)
        If Job.JobName = "readtbl" Then
            Dim mytrack As List
            Dim strOnline As String
            mytrack = parser.NextArray 'returns a list with maps
            For i = 0 To mytrack.Size - 1
                Dim t As Map
                t = mytrack.Get(i)
                Dim TL As TwoLines
          
                TL.First = t.Get("user_id") & t.Get("date") & t.Get("time")
                TL.Second = t.Get("longitude") & t.Get("latitude")
                ListView1.AddTwoLines2(TL.First, TL.Second, TL)
          
          
            Next
        Else If Job.JobName = "LogOut" Then
            Dim act As String = parser.NextValue
            If act = "LoggedOut" Then
                ToastMessageShow("Logout successful", True)          
                StartActivity(Main)
                Activity.Finish
            End If          
        Else
            ToastMessageShow("Error: Invalid Value", True)
        End If
    Else
        'Log("Error: " & Job.ErrorMessage)
        ToastMessageShow("Error: " & Job.ErrorMessage, True)
    End If
    Job.Release
End Sub

<?
$host = "localhost";
$db = "mydb";
$user = "myuser";
$pw = "123";

$con = mysql_connect($host, $user, $pw) or die(mysql_error());
mysql_select_db($db) or die(mysql_error());
mysql_query("SET CHARACTER SET utf8");
mysql_query("SET NAMES 'utf8'");

$uid = mysql_real_escape_string($_GET["user_id"]);

$res = mysql_query("SELECT user_id, date , time , latitude , longitude FROM tbl_track WHERE user_id = '$uid'");
if (!$res) {
    print json_encode("Error");
    echo "<br />" . mysql_error();
    exit;
}
else {
    if (mysql_num_rows($res) == 0) {
        print json_encode("Not Found");
        exit;
    }
    $row = mysql_fetch_row($res);

    }
    else {
        print json_encode($row[0]);
    }
}
?>