I am creating my first program and I have had some success just until now. When I simulate my program using release, it gives me the following error:

@Error loading "qmfstoragemanagerd.dll" with errorString() "The plugin 'C:/QtSDK/Simulator/Qt/mingw/plugins/contentmanagers/qmfstoragemanagerd.dll' uses incompatible Qt library. Expected build key "Windows mingw release full-config", got "Windows mingw debug full-config""
QSqlDatabasePrivate::removeDatabase: connection 'qt_sql_default_connection' is still in use, all queries will cease to work.@

It will then freeze when I call saveData() under the popupinput class. I do not know if it is my code or my QT creator as I have only installed the basic QT SDK.

Heres my code for the popupinput class:

header:
@#ifndef POPUPINPUT_H
#define POPUPINPUT_H
#include <QDialog>
#include <QLabel>
#include <QFormLayout>
#include <QGridLayout>
#include <QPushButton>
#include <QLineEdit>
#include <QFile>

class PopupInput: public QDialog
{
Q_OBJECT

public:
PopupInput(QWidget *parent = 0);

public slots:
void saveData();

private:
QPushButton *save;
QPushButton *cancel;
QString station;
QString bus;
QString busStopNumber;
QLineEdit *stationEdit;
QLineEdit *busEdit;
QLineEdit *busStopNumberEdit;

};
#endif
@

cpp:

@#include <QtGui>
#include "popupinput.h"
#include <QDebug>
#include <QMessageBox>
PopupInput::PopupInput(QWidget *parent)
:QDialog(parent)
{
QLabel *busLabel= new QLabel(tr("Bus:"));
QLabel *stationLabel= new QLabel(tr("Station:"));
QLabel *busStopNumberLabel= new QLabel(tr("Bus Stop Number:"));

save=new QPushButton(tr("&Save"));
cancel=new QPushButton(tr("&Cancel"));

bus="";
station="";
busStopNumber="";

busEdit=new QLineEdit;
stationEdit=new QLineEdit;
busStopNumberEdit=new QLineEdit;

QFormLayout *layout = new QFormLayout;

layout->addRow(busLabel, busEdit);
layout->addRow(stationLabel,stationEdit);
layout->addRow(busStopNumberLabel, busStopNumberEdit);

QGridLayout *grid= new QGridLayout;
grid->addWidget(cancel,1,0,Qt::AlignRight);
grid->addWidget(save,0,0,Qt::AlignRight);
layout->addRow(grid);
setLayout(layout);
connect(save, SIGNAL(clicked()), this, SLOT(saveData()));
connect(save, SIGNAL(clicked()), this, SLOT(accept()));
connect(cancel, SIGNAL(clicked()), this, SLOT(accept()));

}

void PopupInput::saveData()
{

 QFile file( "a.txt" );
 //QFile file("d://out.txt");

 if( !file.exists() )
 {

     file.open(QIODevice::WriteOnly | QIODevice::Text);
     QTextStream out(&file);
     out << "This file is generated by Qt\n";

     file.close();


    qDebug()<<"created";
 }
 else
 {


    qDebug()<<"exists";
 }
 file.close();

}
@

Thanks in advance