(The part support bed dropped just before starting the part,
so I must have done something strange I do not know about.
Ended up with a lump on the end of the extruder being whipped into some shape by sliding on the Kapton).

Problem # 2: "Unhandled exception has occurred in your application. . . . "
Solved.
Again, changed from Repetier-Host version 0.85 to Repetier-Host version 0.90.

Just checked the "About" box for Repetier-Host.
The company and the programmer are not mentioned.
From my time in Commerce, a good way to "pay" someone is to give them credit when they do a good job.

GOOD JOB REPETIER-HOST PROGRAMMER!

The programmer also has a PayPal button if you search for it.

James.

From "Extrude clicked: Test= . . ."
   suggestions to fix the behaviour of an SD2 led to:

1. When I felt the filament going into the head of the extruder, it was going in
           - but   then   coming   out   the   same   distance  (!)

and also,

2.  "Looked at the scrolling log, and wanted to use a search tool on it.
                      - Clicked on "Copy" as an experiment.
                     ...
                       "Unhandled exception has occurred in your application. . . . "
                         [Details]
                                       "***********Exception Text*********
                                         System.ArgumentOutOfRangeException: Index was out of range.
                                         Parameter name: index
                                         at System.ThrowHelper.ThrowArgumentOutOfRangeException(ExceptionArgument
                                         at System.Throwhelper.   "()
                                         at RepetierHost.view.LogBox.getSelection()
                                         at RepetierHost.view.LogView.toolCopy_Cllick(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(MouseEventsArgs 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)
                                         "
I am uncertain how to eliminate either symptom.

Thanks to   2n2r5,   ronsii,   Claghorn,  and   Hazer, who brought me to this point.

James.