unhandled exception has occurred in your application .net framework

Since roughly 1 month ago I am having more and more cases of this error with different customers

Below is the data from the error for the first one.

See the end of this message for details on invoking
just-in-time (JIT) debugging instead of this dialog box.
 
************** Exception Text **************
System.NullReferenceException: Object reference not set to an instance of an object.
   at Triality.Frm_Edit_Trial.btnPrint_Click(Object sender, EventArgs e)
   at System.Windows.Forms.Control.OnClick(EventArgs e)
   at System.Windows.Forms.Button.OnClick(EventArgs e)
   at System.Windows.Forms.Button.OnMouseUp(MouseEventArgs mevent)
   at VIBlend.WinForms.Controls.vButton.OnMouseUp(MouseEventArgs mevent)
   at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)
   at System.Windows.Forms.Control.WndProc(Message& m)
   at System.Windows.Forms.ButtonBase.WndProc(Message& m)
   at System.Windows.Forms.Button.WndProc(Message& m)
   at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
   at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
   at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
 
 
************** Loaded Assemblies **************
mscorlib
    Assembly Version: 2.0.0.0
   Win32 Version: 2.0.50727.5485 (Win7SP1GDR.050727-5400)
    CodeBase: file:///C:/Windows/Microsoft.NET/Framework/v2.0.50727/mscorlib.dll
----------------------------------------
Triality
    Assembly Version: 1.0.0.0
    Win32 Version: 1.0.0.0
    CodeBase: file:///C:/Program%20Files%20(x86)/Regal%20Grange/Triality/Triality.exe
----------------------------------------
Microsoft.VisualBasic
    Assembly Version: 8.0.0.0
    Win32 Version: 8.0.50727.5483 (Win7SP1GDR.050727-5400)
    CodeBase: file:///C:/Windows/assembly/GAC_MSIL/Microsoft.VisualBasic/8.0.0.0__b03f5f7f11d50a3a/Microsoft.VisualBasic.dll
----------------------------------------
System
    Assembly Version: 2.0.0.0
    Win32 Version: 2.0.50727.5485 (Win7SP1GDR.050727-5400)
    CodeBase: file:///C:/Windows/assembly/GAC_MSIL/System/2.0.0.0__b77a5c561934e089/System.dll
----------------------------------------
System.Windows.Forms
    Assembly Version: 2.0.0.0
    Win32 Version: 2.0.50727.5491 (Win7SP1GDR.050727-5400)
    CodeBase: file:///C:/Windows/assembly/GAC_MSIL/System.Windows.Forms/2.0.0.0__b77a5c561934e089/System.Windows.Forms.dll
----------------------------------------
System.Drawing
    Assembly Version: 2.0.0.0
    Win32 Version: 2.0.50727.5491 (Win7SP1GDR.050727-5400)
    CodeBase: file:///C:/Windows/assembly/GAC_MSIL/System.Drawing/2.0.0.0__b03f5f7f11d50a3a/System.Drawing.dll
----------------------------------------
System.Runtime.Remoting
    Assembly Version: 2.0.0.0
    Win32 Version: 2.0.50727.5488 (Win7SP1GDR.050727-5400)
    CodeBase: file:///C:/Windows/assembly/GAC_MSIL/System.Runtime.Remoting/2.0.0.0__b77a5c561934e089/System.Runtime.Remoting.dll
----------------------------------------
VIBlendControls
    Assembly Version: 4.5.0.0
    Win32 Version: 4.5.0.0
    CodeBase: file:///C:/Program%20Files%20(x86)/Regal%20Grange/Triality/VIBlendControls.DLL
----------------------------------------
VIBlendUtilities
    Assembly Version: 4.5.0.0
    Win32 Version: 4.5.0.0
    CodeBase: file:///C:/Program%20Files%20(x86)/Regal%20Grange/Triality/VIBlendUtilities.DLL
----------------------------------------
System.Xml
    Assembly Version: 2.0.0.0
    Win32 Version: 2.0.50727.5485 (Win7SP1GDR.050727-5400)
    CodeBase: file:///C:/Windows/assembly/GAC_MSIL/System.Xml/2.0.0.0__b77a5c561934e089/System.Xml.dll
----------------------------------------
System.Configuration
    Assembly Version: 2.0.0.0
    Win32 Version: 2.0.50727.5483 (Win7SP1GDR.050727-5400)
    CodeBase: file:///C:/Windows/assembly/GAC_MSIL/System.Configuration/2.0.0.0__b03f5f7f11d50a3a/System.Configuration.dll
----------------------------------------
lhby4zjg
    Assembly Version: 4.5.0.0
    Win32 Version: 2.0.50727.5485 (Win7SP1GDR.050727-5400)
    CodeBase: file:///C:/Windows/assembly/GAC_MSIL/System/2.0.0.0__b77a5c561934e089/System.dll
----------------------------------------
LidorSystems.IntegralUI
    Assembly Version: 2.2.0.0
    Win32 Version: 2.2.0.0
    CodeBase: file:///C:/Program%20Files%20(x86)/Regal%20Grange/Triality/LidorSystems.IntegralUI.DLL
----------------------------------------
LidorSystems.IntegralUI.Lists
    Assembly Version: 2.2.0.0
    Win32 Version: 2.2.0.0
    CodeBase: file:///C:/Program%20Files%20(x86)/Regal%20Grange/Triality/LidorSystems.IntegralUI.Lists.DLL
----------------------------------------
LidorSystems.IntegralUI.Lists.ListView
    Assembly Version: 2.2.0.0
    Win32 Version: 2.2.0.0
    CodeBase: file:///C:/Program%20Files%20(x86)/Regal%20Grange/Triality/LidorSystems.IntegralUI.Lists.ListView.DLL
----------------------------------------
WinHTMLEditorControl
    Assembly Version: 4.0.6.39
    Win32 Version: 4.0.6.39
    CodeBase: file:///C:/Program%20Files%20(x86)/Regal%20Grange/Triality/WinHTMLEditorControl.DLL
----------------------------------------
Microsoft.mshtml
    Assembly Version: 7.0.3300.0
    Win32 Version: 7.0.3300.0
    CodeBase: file:///C:/Windows/assembly/GAC/Microsoft.mshtml/7.0.3300.0__b03f5f7f11d50a3a/Microsoft.mshtml.dll
----------------------------------------
System.Security
    Assembly Version: 2.0.0.0
    Win32 Version: 2.0.50727.5490 (Win7SP1GDR.050727-5400)
    CodeBase: file:///C:/Windows/assembly/GAC_MSIL/System.Security/2.0.0.0__b03f5f7f11d50a3a/System.Security.dll
----------------------------------------
LidorSystems.IntegralUI.Lists.ListBox
    Assembly Version: 1.2.0.0
    Win32 Version: 1.2.0.0
    CodeBase: file:///C:/Program%20Files%20(x86)/Regal%20Grange/Triality/LidorSystems.IntegralUI.Lists.ListBox.DLL
----------------------------------------
System.Web.Services
    Assembly Version: 2.0.0.0
    Win32 Version: 2.0.50727.5483 (Win7SP1GDR.050727-5400)
    CodeBase: file:///C:/Windows/assembly/GAC_MSIL/System.Web.Services/2.0.0.0__b03f5f7f11d50a3a/System.Web.Services.dll
----------------------------------------
sylnzt1i
    Assembly Version: 1.0.0.0
    Win32 Version: 2.0.50727.5485 (Win7SP1GDR.050727-5400)
    CodeBase: file:///C:/Windows/assembly/GAC_MSIL/System/2.0.0.0__b77a5c561934e089/System.dll
----------------------------------------
System.Data
    Assembly Version: 2.0.0.0
    Win32 Version: 2.0.50727.5483 (Win7SP1GDR.050727-5400)
    CodeBase: file:///C:/Windows/assembly/GAC_32/System.Data/2.0.0.0__b77a5c561934e089/System.Data.dll
----------------------------------------
System.Transactions
    Assembly Version: 2.0.0.0
    Win32 Version: 2.0.50727.5483 (Win7SP1GDR.050727-5400)
    CodeBase: file:///C:/Windows/assembly/GAC_32/System.Transactions/2.0.0.0__b77a5c561934e089/System.Transactions.dll
----------------------------------------
System.EnterpriseServices
    Assembly Version: 2.0.0.0
    Win32 Version: 2.0.50727.5483 (Win7SP1GDR.050727-5400)
    CodeBase: file:///C:/Windows/assembly/GAC_32/System.EnterpriseServices/2.0.0.0__b03f5f7f11d50a3a/System.EnterpriseServices.dll
----------------------------------------
Accessibility
    Assembly Version: 2.0.0.0
    Win32 Version: 2.0.50727.5483 (Win7SP1GDR.050727-5400)
    CodeBase: file:///C:/Windows/assembly/GAC_MSIL/Accessibility/2.0.0.0__b03f5f7f11d50a3a/Accessibility.dll
----------------------------------------
ffmphnaw
    Assembly Version: 1.0.0.0
    Win32 Version: 2.0.50727.5485 (Win7SP1GDR.050727-5400)
    CodeBase: file:///C:/Windows/assembly/GAC_MSIL/System/2.0.0.0__b77a5c561934e089/System.dll
----------------------------------------
 
************** JIT Debugging **************
To enable just-in-time (JIT) debugging, the .config file for this
application or computer (machine.config) must have the
jitDebugging value set in the system.windows.forms section.
The application must also be compiled with debugging
enabled.
 
For example:
 
<configuration>
    <system.windows.forms jitDebugging="true" />
</configuration>
 
When JIT debugging is enabled, any unhandled exception
will be sent to the JIT debugger registered on the computer
rather than be handled by this dialog box.

The next one is a slightly different error.


Both clients seem to have got these errors about 1 month ago, Suspect an update has broken something.
Have tried a repair and reinstall of .net framework 4.5 but issue still exists..