The code in the article you sent seems like it should work.  However, the
macro will insert the text fine if the text in the cell is less than 255
characters, but still leaves the text box blank for strings larger than 255.  
Here is what I am using...

Sub Cell_Text_To_TextBox()

     ' Dimension the variables.
     Dim txtBox1 As TextBox
     Dim theRange As Range, cell As Range
     Dim startPos As Integer
     Set wks1 = Worksheets("Patient1")
     ' Set txtBox1 equal to the active sheet's TextBox object. You can
     ' replace the ordinal number with your text box name in quotes.
     ' For example: ActiveSheet.DrawingObjects("Text 1")
     Set txtBox1 = wks1.DrawingObjects("Text Box 36")

     ' Set a range on the active sheet equal to the range object text
     ' that you are interested in copying to the text box.
     Set theRange = ActiveSheet.Range("D42:D72")

     'Set the starting position for the text.
     startPos = 1

     ' Create a For-Each construct to loop through the cells in the range.
     For Each cell In theRange

        ' Populate the textbox with the cell values using the Characters
        ' method.
        ' Note: Chr(10) can be used to add a new line in the textbox for
        ' each cell.
        txtBox1.Characters(Start:=startPos, _
        Length:=Len(cell.Value)).Text = cell.Value & Chr(10)
        ' Update the startPos variable to keep track of where the next
        ' string of text will begin in the textbox.
        startPos = startPos + Len(cell.Value) + 1

     Next cell
  End Sub

I did get this solution to work, however, the text I need displayed exists in
multiple cells, depending on values entered in the sheet and the resulting
vlookup.  I could not find a way to link a control text box to a range of
cells.  :(