Fix crash in PtGetCameraNumber()

Sources/Plasma/FeatureLib/pfCamera/plVirtualCamNeu.cpp

@@ -227,7 +227,10 @@ plVirtualCam1::~plVirtualCam1()
 // for saving camera stack
 plCameraModifier1* plVirtualCam1::GetCameraNumber(size_t camNumber)
 {
-    return (fCameraStack[camNumber]); 
+    if (fCameraStack.size() > camNumber)
+        return fCameraStack[camNumber];
+    else
+        return nil;
 }
 // for rebuilding camera stack
 void plVirtualCam1::RebuildStack(const plKey& key)

Sources/Plasma/FeatureLib/pfPython/cyMisc.cpp

@@ -2462,7 +2462,7 @@ int cyMisc::GetNumCameras()
 const char* cyMisc::GetCameraNumber(int number)
 {
     plCameraModifier1* pCam = plVirtualCam1::Instance()->GetCameraNumber(number-1);
-    if (pCam->GetTarget())
+    if (pCam && pCam->GetTarget())
     {
         const char* ret = pCam->GetTarget()->GetKeyName().c_str();
         plString str = plString::Format("saving camera named %s to chronicle\n",ret);