Product Does Not Appear On Admin or Store After Insert

Hello,

Here are the conditions: Fresh manual install, PHP Version 5.5.
After installation, I used EP to import products and all went well. I have also been able to delete products through admin interface. However, when attempting to add a product via admin interface it does not add the product after going through the process. It appears like a normal addition of the product and then goes back to the admin interface where the product is not listed, and it appears no where I can find.

Any idea?

Thanks

Any mydebug files in your logs folder? Contents? (Obscure admin folder name if present)
What happens if you edit one of the product that has been entered by whatever version of EP? (Be sure to backup before testing or use EP to enter a disabled product and then try to edit it manually.)

mc12345678:

Any mydebug files in your logs folder? Contents? (Obscure admin folder name if present)
What happens if you edit one of the product that has been entered by whatever version of EP? (Be sure to backup before testing or use EP to enter a disabled product and then try to edit it manually.)

Thanks for your quick reply. I had an emergency and couldn't get to this project.
Editing is fine.
Debug reads PHP Warning: Creating default object from empty value (which I may be able to work out when I am back to this later today, but any thoughts are appreciated) /home/cpanel_username/public_html/my_admin_folder_unique_name/categories.php

This happened at line 1006.

Also, I cannot create categories.

See if the following thread addresses/relates...

https://www.zen-cart.com/showthread.php?215844-Admin-categories-search-Creating-default-object-from-empty-value-%28see-in-debug-logs)

The debugs files are producing the same warning but of course this is a functional problem. It is definitely causing pID=0 on insert. Tried other PHP 5.3, 5.4, 5.5..same results

So couple of things come to mind, though in some respects don't see how a few of them could be the cause seeing as other methods of adding product work.

One thought was that the product_id field of the (YOUR_DB_PREFIX)products table wasn't set to auto increment or that the database record holder for the next number is/was damaged.
Next is the files for the product_type in admin are damaged/corrupt/changed causing the pID=0 issue. Test(s) to try: add a product of a different type and see if successfully added, do so either until a product is successfully added or all product types have been tried, whichever occurs first. Report the results.
Verify by comparison to a vanilla install/fileset that none of the product type files have been modified. Not at my computer, but I thought they were located at: admin/includes/modules with specific product type deviations in a sub-directory for each product type. Been a little while since I've messed with product types enough to recall the exact path.
Did you only read about/up to the discussion of PHP versions? Or did you get down to the end of the first pge of the previous post that suggested commenting out some lines or inserting a new line before the one that is causing that mydebug log?