[Done v155] PHP Fatal error: 1062:Duplicate entry for key 'PRIMARY' :: db_cache

Would really appreciate some guidance on trying to resolve the below PHP Fatal Error:

[20-Jan-2016 13:29:44 EST5EDT] PHP Fatal error: 1062: Duplicate entry 'zc_6ec65decb95a7741ada473af0fde76e1' for key 'PRIMARY' :: insert into zen_db_cache set cache_entry_name = 'zc_6ec65decb95a7741ada473af0fde76e1',
cache_data = 'XXXXXXXXXXXXXXXXXX',
cache_entry_created = '1453314584' ==> (as called by) /public_html/store/includes/classes/cache.php on line 131 <== in /public_html/store/includes/classes/db/mysql/query_factory.php on line 155

XXXXXXXXXXXX in the cache_data = section take the place of a very long list of random characters.

Thank you in advance.

See: http://www.zen-cart.com/showthread.php?215694-Known-Bugs-%28and-fixes%29-with-v1-5-4

For that and other known issues/fixes...

Thank you so very much for the information and the very quick reply. Installed all of DrByte's code revisions. Will test some more and see what happens? Thanks again.

RJR:

Thank you so very much for the information and the very quick reply. Installed all of DrByte's code revisions. Will test some more and see what happens? Thanks again.
Welcome. BTW, there are some other "updates" (Security fixes) that were identified in November of 2015 and can be found at: https://www.zen-cart.com/forumdisplay.php?2-Zen-Cart-Release-Announcements While there, should subscribe to it so that can get other recent update notifications etc...