I would not use the term "screw-up" from the pulpit, though, frankly, if I heard someone else use it, I don't think I'd be terribly bothered by it. The use of "screw" in this sense was reserved for the locker-room for many years in US culture. I think it came out when the Nixon tapes were released and people heard the President speaking of "screwing" his opponents and were shocked at his language. Now, in my work in car sales, I hear this term so often that it is no longer colorful to me,thouigh I don't use it myself because I am aware of its history and its connotation.
I can certainly understand that someone could hear a preacher use it and get offended. In your case, this is what happened. I think, in your situation you need to resolve not to use the term again, from the pulpit. You need to approach the person who was offended and apologize and you probably need to apologize for the language from the pulpit. If you ever get the opportunity to come to Philly and preach, you can use the term liberally and I doubt anyone will care.
IMPORTANT NOTE:
If you apologize, don't get up and say, "sorry, guys, I screwed up."
Kinda kills the momentum.