App runs, crashes if user presses button ( Could not load file or assembly 'System.Core )

Question

I'm confused here, the application is running, which from my current understanding shouldn't be the case if System.Core is not found since this relates to .NET 3.5.1 not being installed or, is possibly corrupted and allowing partial part of the application to load? This is Windows 2008 R2 Server 64bit with .NET 3.5.1 Installed. Assuming its enabled since program loads up.

Full stack trace:

************** Exception Text ************** 
System.IO.FileNotFoundException: Could not load file or assembly 'System.Core, Version=3.5.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' or one of its dependencies. The system cannot find the file specified. 
File name: 'System.Core, Version=3.5.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' 
   at TpaDeployment.AD.Nodes.GetSelectedNodes() 
   at TpaDeployment.DeploymentForm.installButton_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 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) 

WRN: Assembly binding logging is turned OFF. 
To enable assembly bind failure logging, set the registry value [HKLM\Software\Microsoft\Fusion!EnableLog] (DWORD) to 1. 
Note: There is some performance penalty associated with assembly bind failure logging. 
To turn this feature off, remove the registry value [HKLM\Software\Microsoft\Fusion!EnableLog]. 



************** Loaded Assemblies ************** 
mscorlib 
    Assembly Version: 2.0.0.0 
    Win32 Version: 2.0.50727.5466 (Win7SP1GDR.050727-5400) 
    CodeBase: file:///C:/Windows/Microsoft.NET/Framework/v2.0.50727/mscorlib.dll 
---------------------------------------- 
TpaDeployment 
    Assembly Version: 1.0.0.0 
    Win32 Version: 1.0.5.0 
    CodeBase: file:///C:/Users/mdacostaadmin/Desktop/TopPatch%20Deployment/TpaDeployment(1).exe 
---------------------------------------- 
System.Windows.Forms 
    Assembly Version: 2.0.0.0 
    Win32 Version: 2.0.50727.5468 (Win7SP1GDR.050727-5400) 
    CodeBase: file:///C:/Windows/assembly/GAC_MSIL/System.Windows.Forms/2.0.0.0__b77a5c561934e089/System.Windows.Forms.dll 
---------------------------------------- 
System 
    Assembly Version: 2.0.0.0 
    Win32 Version: 2.0.50727.5467 (Win7SP1GDR.050727-5400) 
    CodeBase: file:///C:/Windows/assembly/GAC_MSIL/System/2.0.0.0__b77a5c561934e089/System.dll 
---------------------------------------- 
System.Drawing 
    Assembly Version: 2.0.0.0 
    Win32 Version: 2.0.50727.5467 (Win7SP1GDR.050727-5400) 
    CodeBase: file:///C:/Windows/assembly/GAC_MSIL/System.Drawing/2.0.0.0__b03f5f7f11d50a3a/System.Drawing.dll 
---------------------------------------- 
System.DirectoryServices 
    Assembly Version: 2.0.0.0 
    Win32 Version: 2.0.50727.5467 (Win7SP1GDR.050727-5400) 
    CodeBase: file:///C:/Windows/assembly/GAC_MSIL/System.DirectoryServices/2.0.0.0__b03f5f7f11d50a3a/System.DirectoryServices.dll 
---------------------------------------- 
System.Configuration 
    Assembly Version: 2.0.0.0 
    Win32 Version: 2.0.50727.5420 (Win7SP1.050727-5400) 
    CodeBase: file:///C:/Windows/assembly/GAC_MSIL/System.Configuration/2.0.0.0__b03f5f7f11d50a3a/System.Configuration.dll 
---------------------------------------- 
System.Xml 
    Assembly Version: 2.0.0.0 
    Win32 Version: 2.0.50727.5420 (Win7SP1.050727-5400) 
    CodeBase: file:///C:/Windows/assembly/GAC_MSIL/System.Xml/2.0.0.0__b77a5c561934e089/System.Xml.dll 
---------------------------------------- 
Accessibility 
    Assembly Version: 2.0.0.0 
    Win32 Version: 2.0.50727.4927 (NetFXspW7.050727-4900) 
    CodeBase: file:///C:/Windows/assembly/GAC_MSIL/Accessibility/2.0.0.0__b03f5f7f11d50a3a/Accessibility.dll 
----------------------------------------

System.IO.FileNotFoundException: Could not load file or assembly 'System.Core, Version=3.5.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' or one of its dependencies. The system cannot find the file specified. File name: 'System.Core, Version=3.5.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'

Answer 1

The issue was resolved, .NET 3.5.1 was corrupted on the client's machine.

By running the following Microsoft Fix it Tool, the problem was resolved. http://www.microsoft.com/en-us/download/details.aspx?id=30135