QDesktopServices problem

[jyoti]

hi all
i am using Qt4.1.4
i am facing very small problem
i wanna open an external page
i had created code like this

void MainForm::openHelp()
{
 
	QDesktopServices::openUrl(QUrl("http://www.google.com/"));
}

void MainForm::openHelp()
{

	QDesktopServices::openUrl(QUrl("http://www.google.com/"));
}

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but its giving some errors

MainForm.cpp:21:27: error: QDesktopService: No such file or directory
MainForm.cpp: In member function 'void MainForm::openHelp()':
MainForm.cpp:81: error: 'QDesktopService' has not been declared
MainForm.cpp:81: error: 'openUrl' was not declared in this scope

Build failed (3 errors, 1 warning)

is there any alternative just like as QDesktopServices in QT4.1.4 otherwise tell how to open external link on QT4.1.4

plz do tell if as soon as possible ....