Torvista,
You will be pleased to hear that the simplest solution worked, and then a simpler solution magically appeared.
First, I found the link between categories and subcategories in the PHPMyAdmin categories table, which contains a categories_id plus a parent_id for the category.
Since all categories appeared in that table for Language 1 (English), no entry was needed for Language 2. Therefore, entering a category in the categories_description table was indeed all that was needed to correct the display in the Zen Cart second language category name that wouldn't previously save.
But before making all the additions, I purchased Easy Populate Advanced 3.03, which I read in another thread would upload second language files: zencartbuilder.com
Identifying the path for the uploads file was tricky (found in admin/includes/configure.php at DIR_FS_CATALOG), but after installing, and then downloading the example Easy Populate template and data files, my single main category and 50 sub-categories magically appeared in the Spanish display along with icons which had been missing. There was an incongruity in the top category's missing file name, a capitalization error.
When I had used Easy Populate 1.2.5.4 for my original upload, I had not originally created any of the categories by hand, because 1.2.5.4 usually creates the categories. I now believe that, had I added the Spanish category names by hand, either in PHPMyAdmin or through Admin, version 1.2.5.4 would have been sufficient for uploading products and categories.
In Post 66, I mentioned I had added language 2 capacity to the products_description table in PHPMyAdmin, and now it appears the Spanish category names are easily added to the categories_description table.
Once I had added the language pack and downloaded a sample template, the Spanish descriptions appeared in the downloaded sample file. But so far, the Spanish category name has not appeared in a template download in either version of Easy Populate.
The Advanced program states one must add a column to get the Spanish translation into the second language category name, so in that respect the Advanced version really isn't different from 1.2.5.4. That will take some research to accomplish.
The missing and unsavable Spanish categories seemed a difficult problem. The stunning performance of Easy Populate Advanced 3.03 is really something to shout about. But so is your and Dr. Byte's help which led to the manual solution of this problem and the propagation of other new ideas that have come my way since delving into the Spanish Language Pack. So I am in awe once again.
Notageek