I would rather not pour concrete. Is there anything else I
can use to fill in the hole around the shower drain pipe
shown in the photos at site
http://honda.lioness.googlepages.com/showerdrain ? Any other
suggestions for remedying this as professionally as
possible?

The (Aqua Glass) shower pan cracked so I am replacing it.
The main cause seems to be simply that the floor beneath it
was neither solid nor level.