diff --git a/direct/src/plugin/p3dPackage.cxx b/direct/src/plugin/p3dPackage.cxx
index ed77638311..91d535c14b 100755
--- a/direct/src/plugin/p3dPackage.cxx
+++ b/direct/src/plugin/p3dPackage.cxx
@@ -396,7 +396,8 @@ extract_archive() {
 ////////////////////////////////////////////////////////////////////
 void P3DPackage::
 report_done(bool success) {
-  cerr << "report_done(" << success << ")\n";
+  cerr << "report_done(" << success << "), "
+       << _callbacks.size() << " callbacks\n";
   if (success) {
     _ready = true;
     _failed = false;
@@ -503,6 +504,15 @@ stream_hex(ostream &out, const unsigned char *source, size_t size) {
   }
 }
 
+////////////////////////////////////////////////////////////////////
+//     Function: P3DPackage::Callback::package_ready
+//       Access: Public
+//  Description: 
+////////////////////////////////////////////////////////////////////
+void P3DPackage::Callback::
+package_ready(P3DPackage *package, bool success) {
+}
+
 ////////////////////////////////////////////////////////////////////
 //     Function: P3DPackage::Download::Constructor
 //       Access: Public
diff --git a/direct/src/plugin/p3dSession.cxx b/direct/src/plugin/p3dSession.cxx
index 513e513da3..a1e72af918 100644
--- a/direct/src/plugin/p3dSession.cxx
+++ b/direct/src/plugin/p3dSession.cxx
@@ -141,7 +141,7 @@ start_instance(P3DInstance *inst) {
     start_p3dpython();
   } else {
     // Otherwise, set a callback, so we'll know when it is ready.
-    if (_panda3d_callback != NULL) {
+    if (_panda3d_callback == NULL) {
       _panda3d_callback = new PackageCallback(this);
       _panda3d->set_callback(_panda3d_callback);
     }
@@ -635,7 +635,8 @@ posix_create_process(const string &program, const string &start_dir,
 //  Description: 
 ////////////////////////////////////////////////////////////////////
 P3DSession::PackageCallback::
-PackageCallback(P3DSession *session) {
+PackageCallback(P3DSession *session) : _session(session)
+{
 }
 
 ////////////////////////////////////////////////////////////////////
@@ -645,5 +646,15 @@ PackageCallback(P3DSession *session) {
 ////////////////////////////////////////////////////////////////////
 void P3DSession::PackageCallback::
 package_ready(P3DPackage *package, bool success) {
+  if (this == _session->_panda3d_callback) {
+    _session->_panda3d_callback = NULL;
+    if (package == _session->_panda3d) {
+      _session->start_p3dpython();
+    } else {
+      cerr << "Unexpected panda3d package: " << package << "\n";
+    }
+  } else {
+    cerr << "Unexpected callback for P3DSession\n";
+  }
 }