Looks like at least /includes/languages/english/checkout_process.php is missing.

RULE OF THUMB: Whenever a plugin author like Numinix says "just delete the files" for uninstall instructions, DON'T BELIEVE THEM!!!!! (ref: http://www.zen-cart.com/showthread.p...65#post1273965 ). Always first make sure their files didn't replace files you originally had in that folder by the same name, and be sure to then put back the originals that you had replaced.

I wish plugin authors would put their additions in non-core files more reliably; that's what the extra_definitions folder is for.