Thanks Mike. My problem was that I added a new tax code, marked it as taxable, and added it to the taxable schedules. I also added the new code to a misc item code. When the misc item code was used with a customer with a NONTAX tax schedule, it generated an error because I couldn't add the new code to the ""Nontaxable"" schedule. I got around it by creating a new NONTAX schedule.