error in cll events

[Shanka]

MY USER CONTROL XAML

<UserControl x:Class="CommonControl.PagingBar"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
   xmlns:PagingBar="clr-namespace:CommonControl;assembly=CommonControl"
    Height="38" Width="304" xmlns:telerik="http://schemas.telerik.com/2008/xaml/presentation">
    <StackPanel Height="34" Width="300">      
        <telerik:RadButton Name="btnPaginStart" Click="btnPaginStart_Click" HorizontalAlignment="Left" Margin="5,5,0,-24" Height="24" Width="24"   >|&lt;</telerik:RadButton>
        <telerik:RadButton Name="btnPaginEnd" Click="btnPaginEnd_Click" HorizontalAlignment="Left" Margin="220,0,0,-24" Height="24" Width="24" >&gt;|</telerik:RadButton>
        <telerik:RadButton Name="btnPaginPrevious" Click="btnPaginPrevious_Click" HorizontalAlignment="Left" Margin="35,0,0,-24" Height="24" Width="24" >&lt;</telerik:RadButton>
        <telerik:RadButton Name="btnPaginNext" Click="btnPaginNext_Click" Margin="190,0,0,0"  HorizontalAlignment="Left" Height="24" Width="24">&gt;</telerik:RadButton>
        <my:IntegerInput Height="18" Margin="-50,-20,0,0" Name="integerInput1" ValueChanged="integerInput1_ValueChanged" Width="120"  xmlns:my="clr-namespace:DevComponents.WpfEditors;assembly=DevComponents.WpfEditors" />
    </StackPanel>
</UserControl>


XAML.CS

public event EventHandler pgnPaging_EventExecuteLoad;

private void btnPaginEnd_Click(object sender, RoutedEventArgs e)
        {
         // WANT TO CALL EVENT IN BUTTON CLICK
          pgnPaging_EventExecuteLoad(NULL,NULL);
        }

USER CONTROL USE IN

 <PagingBar:PagingBar Height="38" VerticalAlignment="Top" HorizontalAlignment="Left" Width="256" ></PagingBar:PagingBar>

WANT TO CALL

public void pgnPaging_EventExecuteLoad(object sender, System.EventArgs e)
        {
            loadGroup(2, 1, 20);            
        }

ERROR IS -  Object reference not set to an instance of an object