Hitting that big "launch" button can be a scary thing to do. I've sent a lot of email campaigns in my time, but I still get a bit of that big-red-button-anxiety bit each time. What...
Yeah - what Pamela said. Support are the only ones that can delete fields once they've been used, and it just gets INCREDIBLY messy as an instance scales and ages if you're creatin...
I've also had this a couple of times where is just seems to be a weird bug in the template saving process - first things first, I'd try validating the template code and reapproving...