How to generate LAI on SNAP 5.0

Hello, i need your help to generate LAI from image sentinel 2 B. When i apply LAI i see on the screen SNAP Error

image

How did you import your data and have you applied any other steps of processing?

Please use SNAP 7.

Thank you for you help

No, i have import bands. After, l have applied LAI’s fonction

Please, how can i have SNAP 7?

Download it from the official site on step.esa.int

Thank you so much for your help