I'm trying to compile qextserialport example called uartassistant. I have downloaded and unpacked qextserialport-1.2beta1.tar.gz. Then I have opened uartassistant example with Qt Creator and try to compile it, but I got this:

../../src/qextserialport_win.cpp: In member function 'bool QextSerialPortPrivate:pen_sys(QFlags<*QIODevice::OpenModeFlag>)':
../../src/qextserialport_win.cpp:115: error: invalid use of incomplete type 'struct QWinEventNotifier'
../../src/qextserialport_p.h:159: error: forward declaration of 'struct QWinEventNotifier'
../../src/qextserialport_win.cpp:117: error: no matching function for call to 'QextSerialPort::connect(QWinEventNotifier*&, const char*, QextSerialPort* const&, const char*, Qt::ConnectionType)'
../../../QtSDK/Desktop/Qt/4.8.0/mingw/include/*QtCore/qobject.h:204: note: candidates are: static bool QObject::connect(const QObject*, const char*, const QObject*, const char*, Qt::ConnectionType)
../../../QtSDK/Desktop/Qt/4.8.0/mingw/include/*QtCore/qobject.h:217: note: static bool QObject::connect(const QObject*, const QMetaMethod&, const QObject*, const QMetaMethod&, Qt::ConnectionType)
../../../QtSDK/Desktop/Qt/4.8.0/mingw/include/*QtCore/qobject.h:337: note: bool QObject::connect(const QObject*, const char*, const char*, Qt::ConnectionType) const
../../src/qextserialport_win.cpp: In member function 'bool QextSerialPortPrivate::close_sys()':
../../src/qextserialport_win.cpp:132: error: invalid use of incomplete type 'struct QWinEventNotifier'
../../src/qextserialport_p.h:159: error: forward declaration of 'struct QWinEventNotifier'
../../src/qextserialport_win.cpp:133: error: invalid use of incomplete type 'struct QWinEventNotifier'
../../src/qextserialport_p.h:159: error: forward declaration of 'struct QWinEventNotifier'
mingw32-make.exe[1]: *** [debug/qextserialport_win.o] Error 1
mingw32-make.exe: *** [debug] Error 2
15:31:42: The process "C:\QtSDK\mingw\bin\mingw32-make.exe" exited with code 2.
Error while building project uartassistant (target: Desktop)
When executing build step 'Make'

What is wrong? Should I have to do something before I try to compile example? My OS is Windows 7 64bit.