CPackageLicense::OnPostForm

function OnPostForm()
{
	$wizard = $this->GetWizard();
	$package = $this->package;

	if ($wizard->IsPrevButtonClick())
		return;

	$agree = $wizard->GetVar("__agree_license");
	if ($agree != "Y")
		$this->SetError(GetMessage("MAIN_WIZARD_LICENSE_STEP_ERROR"));
}