btrials

Okay that was really weird.  I cleared the cache through the admin/storage/ option and seems to work now.

 

It looks like you're missing the field marketplace_id in the cscart4_addons table.  Run this query to add it.
 

ALTER TABLE `cscart4_addons` ADD `marketplace_id` INT( 11 ) UNSIGNED NULL DEFAULT NULL ;

That is an indicator that you have done a partial upgrade.  There will be other problems as a result.

Suggest you restore to previous known good version and do the upgrade again and not interrupt the process.  Patching one table will get you through one issue but may falsely lead you to believe that everything else is okay.

Thank you to both!  The Tool's method brought the access to the above mentioned area back.  

When I was testing few things I did encounter number of issues I hadn't seen so that was new to me; then I did a restore for the latest back up the CS-Cart did originally during the upgrade.

The weird thing is all the upgrades seemed to have gone good although one time it said there was an error.

I may have CS-Cart do an upgrade to the latest?  I'm back at where I first started, "Upgrade 4.3.3.SP1 - 4.3.4 New version: 4.3.4 Release date: Sep 11, 2015".  So my update is rather overdue...