insertion points not responding

Hi guys,

I am trying to insert math formulas (MathML) into my Web page.  The page already exists, I want to replace formula
"pictures" with <m:math> commands.  Trouble is that the insertion point is not working.  It worked maybe three out of 100
trials.  I am wasting a lot of time.

Instructions say to place the cursor where the insertion shall take place.  It does not work.

I understand that it needs space to do so.  I cannot find out how that is done.  Making space (repeated space-bar clicks)
in the source file does not help.  Trying to add space in the display portion does not work either because no space is
added there.  I am at a loss.

Please help.  Rolf