problems database rollback sql

I created a procedure that calls the begin transaction before 3 procedures that make data entry in tables 3. If one of the three procedures is in exception, the rollback does not work.
what am I doing wrong?

See example

Code:

  Sub InsertTicketInterventi(aBO As BusinessObject, req As ServletRequest, resp As ServletResponse)

        mDB.BeginTransaction

        aBO.Master.OkUpdate     = True
        aBO.Detail.OkUpdate     = True
        aBO.Summary.OkUpdate     = True...  

problems database rollback sql

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