Of course, if the error is yours, the proper response is to acknowledge it, briefly explain yourself and indicate your intent to do better: "I apologise. I'm still learning our expense-reporting procedures. I'll review them so this doesn't happen again." No cringing necessary.
Your success with that approach depends on the people and the environment you're dealing with. When the goal is good work, honest mistakes aren't a scarlet brand; they're a side effect of doing business with humans. They can help pinpoint lapses in the system - inconsistent training, byzantine procedures, poor communication - that are due for a tuneup. People feel safe admitting mistakes, because the benefits of honesty outweigh the need to appear perfect. But it's possible no amount of apologising or explaining would have mollified your executive.
The question is whether that person's reaction was typical. In a workplace dominated by goals other than good work - revenue, power, survival - blame is the primary currency. People in those environments aren't interested in problem solving, just keeping the bucks flying. That goes for corporate offices, checkout lanes and tee-ball teams.
To find out where you are, follow up with the person who trained you: "Hey, I thought I understood from my training that I should do X, but now I'm hearing I should do Y. Did I remember that wrong?" Your co-worker's reaction - evade, deny, apologise - will offer clues about his or her trustworthiness and the outlook for this job. Will you learn to do good work or get trapped playing an endless game of hot potato with blame grenades?
Miller has written for and edited tax publications for 16 years, most recently for the accounting firm KPMG's Washington National Tax office.