Disable <enter> Button at Submitting

Is it possible to disable the <enter> button to not submit nor trigger an action?

I have a problem with a course.

In a couple of text fields,when pressing <enter> the course jumps tot he next slide, when is not supposed to.

The functioning should be the next:

1. The learner should write the % sign in the selected text field and press the button next to it.
2. A window opens whith a new text field with the % sign already on it.
3. The learner must write %rivera and click the button next to the text field.
4. The windows turns into another window with just one name on it, the learner must select it and press the Seleccionar button (bottom right).

Well, it turns out, that when I write the % sign on the first textflied and press <enter>, I jump to the next slide.

If I get to the second text field, then, whatever I write on it, I can press <enter> and jump to the next slide. Even if I don't write anything!

I don't understand why does that happen. Any ideas? It would be OK if I could at least disable the <enter> button, but it would be better if I can change whatever that is wrong.

PS: I am only uploading the last slides.