diff --git a/setpath.sh b/setpath.sh
index 08d93218..b7e3a9c6 100755
--- a/setpath.sh
+++ b/setpath.sh
@@ -7,6 +7,16 @@
 #    source setpath.sh   for Zsh or Bash
 #
 
+if [[ "${BASH_SOURCE[0]}" == "${0}" ]]; then
+	echo "The setpath.sh script must be sourced, not executed. In other words, run\n"
+	echo "$ source setpath.sh\n"
+	echo "If you wish to use the Mitsuba Python bindings, you should also specify"
+	echo "your Python version /before/ sourcing setpath.sh, e.g.\n"
+	echo "$ export MITSUBA_PYVER=3.3"
+	echo "$ source setpath.sh"
+	exit 0
+fi
+
 if [ "$BASH_VERSION" ]; then
 	MITSUBA_DIR=$(dirname "$BASH_SOURCE")
 	export MITSUBA_DIR=$(builtin cd "$MITSUBA_DIR"; builtin pwd)
diff --git a/src/libpython/render.cpp b/src/libpython/render.cpp
index 3f718c9a..80fdadb3 100644
--- a/src/libpython/render.cpp
+++ b/src/libpython/render.cpp
@@ -75,7 +75,11 @@ static bp::tuple shape_getNormalDerivative(const Shape *shape, const Intersectio
 	return bp::make_tuple(dpdu, dpdv);
 }
 
-static ref<Scene> loadScene(const fs::path &filename, const StringMap &params) {
+static ref<Scene> loadScene1(const fs::path &filename) {
+	return SceneHandler::loadScene(filename);
+}
+
+static ref<Scene> loadScene2(const fs::path &filename, const StringMap &params) {
 	SceneHandler::ParameterMap pmap;
 	for (StringMap::const_iterator it = params.begin(); it != params.end(); ++it)
 		pmap[it->first]=it->second;
@@ -256,7 +260,8 @@ void export_render() {
 		.def("request2DArray", &Sampler::request2DArray);
 
 	bp::class_<SceneHandler, boost::noncopyable>("SceneHandler", bp::no_init)
-		.def("loadScene", &loadScene, BP_RETURN_VALUE)
+		.def("loadScene", &loadScene1, BP_RETURN_VALUE)
+		.def("loadScene", &loadScene2, BP_RETURN_VALUE)
 		.staticmethod("loadScene");
 
 	BP_CLASS(RenderJob, Thread, (bp::init<const std::string &, Scene *, RenderQueue *>()))