mmx 1.3.1 - Invalid Transaction when adding shares

[alex4]

Hi, newbie here.

I'm using mmx 1.3.1 under windows 10 with english interface and argentina region (decimal separator is comma, date format is dd/mm/yyyy)

I can correctly create a company's stock account with initial balance, however when I add shares I get an "invalid transaction" message without any clues as to what might cause the invalid transaction.

This was done on a new database.

Please help me out!

Any suggestion is welcome.

thanks
Alex