I too, had the same error #1146 with the same message. I have read through this thread and found a few explanations, but none of them worked for me. I ended up comparing the install.sql file that comes with the 1.6.1 release with the older 1.5 version's. I found them to be nearly identical except for the parenthesis:

INSERT INTO `configuration_group` VALUES (NULL, 'Zen Lightbox', 'Configure Zen Lightbox settings', '0', '1');
UPDATE `configuration_group` SET `sort_order` = LAST_INSERT_ID() WHERE `configuration_group_id` = LAST_INSERT_ID();
SELECT (@cgi := `configuration_group_id`) FROM `configuration_group` WHERE `configuration_group_title` = 'Zen Lightbox';

My Zen Lightbox was working until recently. I noticed the other day that there was a compatibility issue with the new Chrome. So after finding the recent Light box update, I decided to do a full reinstall. I usually use phpMyAdmin to upload the install.sql files. However, in this circumstance I was unsuccessful with this method. After some looking around and some trial and error, I applied the two parenthesis and then uploaded using the Zen Cart admin option. Not quite sure why this worked, but felt I should share my experience with the #1146 Error. Please let us all know if this fixed your error.

1.6.1 is almost working perfectly with 1.3.8a. My previous, next and close buttons are not displaying. If I hover over where they should appear, the link or anchor is in tact and functional! Just wanted to let you smarter code guys know in case that helps with a clue. If anyone has figured out how to make the navigation images appear, I thank you ahead of time!