Segmentation fault using sqlite

[vidalpuga]

I know this is a typical error message, but I cannot find a solution in the other post I found on it.
I have the following code:

void Ligas::SetId(const QString s,QSqlDatabase *datos)
{
    if(datos == NULL){
        qDebug() << "NULL database";
        return;
    }
    if(!datos->isOpen()){
        qDebug() << "Failed to open the database";
        return;
    }
    qDebug() << "step 1: " << s;
    setWindowTitle(s);
    qDebug() << "step 2";
    ui->listWidget_estad->clear();
    qDebug() << "step 3";
    ui->listWidget_nombres->clear();
    qDebug() << "step 4";
...
}

void Ligas::SetId(const QString s,QSqlDatabase *datos)
{
    if(datos == NULL){
        qDebug() << "NULL database";
        return;
    }
    if(!datos->isOpen()){
        qDebug() << "Failed to open the database";
        return;
    }
    qDebug() << "step 1: " << s;
    setWindowTitle(s);
    qDebug() << "step 2";
    ui->listWidget_estad->clear();
    qDebug() << "step 3";
    ui->listWidget_nombres->clear();
    qDebug() << "step 4";
...
}

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I get to "Step 1" before the message error:

The inferior stopped because it received a signal from the Operating System.

Signal name : SIGSEGV
Signal meaning : Segmentation fault

If I delete setWindowTitle(s); I get the very same error after Step 2. So I am really confused. Can anybody help me?

The program used to work fine before adding new rows into the database.