Fix kcm_gtk crash when TDE GTK engine is not installed

This resolves Bug 1672

kcm_gtk/kcmgtk.cpp

@@ -234,13 +234,15 @@ void KcmGtk::getInstalledThemes()
 	
 	bool installed = false;
 	widget->styleBox->clear();
-	TQStringList otherStyles = themes.keys();
-	if(!otherStyles.empty()) {
-		otherStyles.remove(otherStyles.find("Qt"));
+	if(!themes.empty()) {
+		TQStringList otherStyles = themes.keys();
+		if(otherStyles.find("Qt")!=otherStyles.end()) {
+			otherStyles.remove(otherStyles.find("Qt"));
+		}
 		installed = !otherStyles.empty();
-	}
-	if(installed) {
-		widget->styleBox->insertStringList(otherStyles);
+		if(installed) {
+			widget->styleBox->insertStringList(otherStyles);
+		}
 	}
 	widget->styleKde->setEnabled(installed);
 	widget->styleBox->setEnabled(installed);
@@ -269,13 +271,15 @@ void KcmGtk::getInstalledThemes()
 	
 	bool gtk3installed = false;
 	widget->styleBox3->clear();
-	TQStringList otherGtk3Styles = gtk3Themes.keys();
-	if(!otherGtk3Styles.empty()) {
-		otherGtk3Styles.remove(otherGtk3Styles.find("tdegtk"));
+	if(!gtk3Themes.empty()) {
+		TQStringList otherGtk3Styles = gtk3Themes.keys();
+		if(otherGtk3Styles.find("tdegtk")!=otherGtk3Styles.end()) {
+			otherGtk3Styles.remove(otherGtk3Styles.find("tdegtk"));
+		}
 		gtk3installed = !otherGtk3Styles.empty();
-	}
-	if(gtk3installed) {
-		widget->styleBox3->insertStringList(otherGtk3Styles);
+		if(gtk3installed) {
+			widget->styleBox3->insertStringList(otherGtk3Styles);
+		}
 	}
 	widget->styleKde3->setEnabled(gtk3installed);
 	widget->styleBox3->setEnabled(gtk3installed);