C# Exception has been thrown by the target of an invocation

I'm having this error when running my C# .net 4.5 windows forms project from IDE or exe, I have no clear or fixed scenario, and I can't find a clue in the exception that is being thrown. I want to know how to get the source of error and fix it, or at least handle it in a way that does not make the exe crashed!
Below are the details of the exception:

Message:

Exception has been thrown by the target of an invocation.

Inner Exception Message:

Attempted to read or write protected memory.
This is often an indication that other memory is corrupt.

Inner Exception Stack Trace:

at
System.Windows.Forms.UnsafeNativeMethods.CallWindowProc(IntPtr
wndProc, IntPtr hWnd, Int32 msg, IntPtr wParam, IntPtr lParam) at
System.Windows.Forms.NativeWindow.DefWndProc(Message& m) at
System.Windows.Forms.Control.DefWndProc(Message& m) at
System.Windows.Forms.Control.WndProc(Message& m) at
System.Windows.Forms.TextBoxBase.WndProc(Message& m) at
System.Windows.Forms.RichTextBox.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.DebuggableCallback(IntPtr
hWnd, Int32 msg, IntPtr wparam, IntPtr lparam) at
System.Windows.Forms.UnsafeNativeMethods.SendMessage(HandleRef hWnd,
Int32 msg, Int32 wParam, EDITSTREAM lParam) at
System.Windows.Forms.RichTextBox.StreamIn(Stream data, Int32 flags)
at System.Windows.Forms.RichTextBox.StreamIn(String str, Int32 flags)
at System.Windows.Forms.RichTextBox.set_Rtf(String value) at
TragTask.UserControls.CommentControl.SetCommentInfo() in
C:\TFS\Tragging\Tragging
Solutions\TragTask\TragTask\UserControls\CommentControl.cs:line 76
at
TragTask.UserControls.CommentControl.set_Comment(TaskMilestoneTimerAndComment
value) in C:\TFS\Tragging\Tragging
Solutions\TragTask\TragTask\UserControls\CommentControl.cs:line 49
at TragTask.Forms.frmTaskDetails.d__24.MoveNext()
in C:\TFS\Tragging\Tragging
Solutions\TragTask\TragTask\Forms\frmTaskDetails.cs:line 339 at
System.Runtime.CompilerServices.AsyncMethodBuilderCore.MoveNextRunner.InvokeMoveNext(Object
stateMachine) at
System.Threading.ExecutionContext.RunInternal(ExecutionContext
executionContext, ContextCallback callback, Object state, Boolean
preserveSyncCtx) at
System.Threading.ExecutionContext.Run(ExecutionContext
executionContext, ContextCallback callback, Object state, Boolean
preserveSyncCtx) at
System.Runtime.CompilerServices.AsyncMethodBuilderCore.MoveNextRunner.Run()
at
System.Runtime.CompilerServices.TaskAwaiter.<>c__DisplayClass11_0.b__0()
at
System.Runtime.CompilerServices.AsyncMethodBuilderCore.ContinuationWrapper.Invoke()
at
System.Threading.Tasks.SynchronizationContextAwaitTaskContinuation.<>c.<.cctor>b__8_0(Object
state)

TargetSite

{System.Object InvokeMethod(System.Object,
System.Object[], System.Signature, Boolean)}

Target Site, Declaring Types:

{Name = "RuntimeMethodHandle" FullName = "System.RuntimeMethodHandle"}

Stack Trace:

at System.RuntimeMethodHandle.InvokeMethod(Object target, Object[]
arguments, Signature sig, Boolean constructor) at
System.Reflection.RuntimeMethodInfo.UnsafeInvokeInternal(Object obj,
Object[] parameters, Object[] arguments) at
System.Delegate.DynamicInvokeImpl(Object[] args) at
System.Windows.Forms.Control.InvokeMarshaledCallbackDo(ThreadMethodEntry
tme) at
System.Windows.Forms.Control.InvokeMarshaledCallbackHelper(Object obj)
at System.Threading.ExecutionContext.RunInternal(ExecutionContext
executionContext, ContextCallback callback, Object state, Boolean
preserveSyncCtx) at
System.Threading.ExecutionContext.Run(ExecutionContext
executionContext, ContextCallback callback, Object state, Boolean
preserveSyncCtx) at
System.Threading.ExecutionContext.Run(ExecutionContext
executionContext, ContextCallback callback, Object state) at
System.Windows.Forms.Control.InvokeMarshaledCallback(ThreadMethodEntry
tme) at System.Windows.Forms.Control.InvokeMarshaledCallbacks()
at System.Windows.Forms.Control.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) at
System.Windows.Forms.UnsafeNativeMethods.DispatchMessageW(MSG& msg)
at
System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(IntPtr
dwComponentID, Int32 reason, Int32 pvLoopData) at
System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32
reason, ApplicationContext context) at
System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32
reason, ApplicationContext context) at
System.Windows.Forms.Application.Run() at TragTask.Program.Main()

Update
After C.Evenhuis pointed out that this has to do with CommentControl.SetCommentInfo method, I thought it would be needed to add this method in my question (note that tb_comment is a RichTextBox control):

public bool SetCommentInfo()
{
    try
    {
        this.SuspendLayout();

        lbl_user.Text = "userName";
        lbl_dateTime.Text = mComment.DateTimeAdded.ToString("dd/MM/yyyy HH:mm:ss");

        if (mComment.Comment.TrimStart().StartsWith("{\\rtf1", StringComparison.Ordinal))
        {
            tb_comment.Clear();
            tb_comment.Text = "";
            tb_comment.Rtf = mComment.Comment;
        }
        else
            tb_comment.Text = mComment.Comment;

        return true;
    }
    catch (Exception ex)
    {
        Utils.Global.ErrorLog("SetCommentInfo", ex, true);
        return false;
    }
    finally
    {
        this.ResumeLayout();
    }
}