Error 11 – Division by Zero in MS-Access Application

Hello,
I am posting here a problem regarding our company application, built in Microsoft Access.
When I was encoding on our survey about study habits of students, I was about to input-in time, an error message popped up with words which pointed to error 11 division zero.

Value: 0.579518616199493
Error Line: 80
Error: (11) Division by zero
This is my first time to encounter this error. I am wondering why other numeric fields accept data without an error, such as age, number of siblings, bedtime hours. But I remember, "the hours spend studying" input field has a new characteristic, it will round off to the nearest 15 minutes of the given hours.
Would this feature make this error possible? Please help me solve my problem.
