Validation function not found. isTagWeight

[omega26]

Hello,

First of all, I want to thank this community for the constant help given to all Prestashop users. More than 3 years I work with this solution, more than 3 years that I read this forum very regularly, finding most solutions to my problems here.
I could not write my very first post without thanking you for having accompanied the sinuous course of an absolute neophyte.

I am addressing you today because I have a concern about 1.6.1.7 version, unable to create or edit products of my shop. 
This error appears: Validation function not found. isTagWeight

I do not understand anything, everything worked well so far and I'm stuck, being able to edit only the quantity of products already online.

Any help is welcome !

Thank you in advance