"Just to be the man who walks at those and mails them for the
latch-year door"

The story:

As with many of my misheard lyrics, it happens when I'm doing
my job of Sign Language interpreting. The song came up at a
rally for a walk-a-thon here in Chicago. And it was at that
moment that I realized I had no idea what this line actually was
(nor, for that matter what it means to "haver"). Luckily, it wasn't
a major part of the event. If it had been a song of any
importance, I would have been screwed.