In certainly sounds like good news, but I'd be hesitant to get too excited until speaking with somebody from the court or prosecutors office to confirm. I'd suggest calling the court again on Monday, and it might not be a bad idea to call a local DUI attorney and talk to them as well. Good luck.
I can't say without looking at the notice but it could be a motion was filed by the prosecutor to dismiss due to the wrong code being entered. This would be unusual as the prosecutor could simply amend the charge to reflect the correct code. Another possibility is that the officer never filed the original of the complaint at the court and the court is planning to dismiss. In either event don't get too excited those dismissals are always without prejudice meaning they could be refiled and they generally are. If your husband has two prior dui's within the last 84 months this one would be a felony, likewise if his license was still suspended from a prior DUI this offense could be a felony. If a prosecutor finds out the case may be a felony the general practice is to dismiss, again without prejudice to allow the County Attorney to review the case to see if it should be filed as a felony. By now you probably called the Court. Whatever the answer was check with a crimminal defense attorney the prosecutor is unlikely to let an extreme DUI fall through the cracks.