The final results ...
The break was the files:
/includes/modules/order_total/ot_zip_tax.php.nodb
/includes/modules/order_total/ot_zip_tax.php
The first one is confusing things as it autoloads and conflicts on class name I renamed it:
/includes/modules/order_total/ot_zip_tax.php_nodb_BROKEN
The second is confusing things because in the languages:
/includes/languages/english/modules/order_total/ot_zip_tax.php
this is the code and not the language file ...
I have renamed both files so they will not autoload:
/includes/modules/order_total/ot_zip_tax.php_nodb_BROKEN
/includes/modules/order_total/ot_zip_tax.php_BROKEN
Notice where I added the _ in the file extentions ... so that they do not autoload ...
To fix the file for zip tax, you could try loading the correct language file:
/includes/languages/english/modules/order_total/ot_zip_tax.php
and then rename:
/includes/modules/order_total/ot_zip_tax.php_BROKEN
back to it's proper name:
/includes/modules/order_total/ot_zip_tax.php