Many of the courses in the Spanish department are designed to be taken in sequence. You have to start with 1010, then you can take 1020, then you can take 2040, and then you can take 2050. After 2050, the variety of courses you can take opens up, but some advanced classes have prerequisites beyond 2050.
We do the best we can to help students understand these prerequisites, and the registration system is set up to check for prerequisites automatically, but it's not perfect. Sometimes "the system" has trouble reading your transcript, especially if your credit is transfered from another school and it doesn't exactly match what we offer here. Please don't hesitate to call if you need help! We can tell you what information we need from you in order to help you enroll. Usually a copy of an unofficial transcript will do the trick.
You can view prerequisites for courses when you are registering through my.unt.edu, and you can also find a list of all courses in the UNT Catalog online: UNT Catalog.