Tels,
Success! Thank you for your helpful advice.
It would not work until I changed *all* instances in the below section from 255 to 160. But in any case, it now works.
For other's reference, here is the section as it appears in my tables.sql file.
-- Jobs performed by parallel apache threads or a command-line daemon CREATE TABLE /*$wgDBprefix*/job ( job_id int(9) unsigned NOT NULL auto_increment,
-- Command name, currently only refreshLinks is defined job_cmd varchar(160) NOT NULL default '',
-- Namespace and title to act on -- Should be 0 and '' if the command does not operate on a title job_namespace int NOT NULL, job_title varchar(160) binary NOT NULL,
-- Any other parameters to the command -- Presently unused, format undefined job_params blob NOT NULL default '',
PRIMARY KEY job_id (job_id), KEY (job_cmd(160), job_namespace, job_title) ) TYPE=InnoDB;
-- Dave M G