diff --git a/CMakeLists.txt b/CMakeLists.txt
index 7136b5269..d976eb87f 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -165,3 +165,14 @@ configure_file (
   
 add_subdirectory(src)
 add_subdirectory(utils)
+
+#-----------------------------------------------------------------------------
+### uninstall target
+#-----------------------------------------------------------------------------
+CONFIGURE_FILE(
+  "${CMAKE_CURRENT_SOURCE_DIR}/CMakeModules/cmake_uninstall.cmake.in"
+  "${CMAKE_CURRENT_BINARY_DIR}/cmake_uninstall.cmake"
+  IMMEDIATE @ONLY)
+ADD_CUSTOM_TARGET(uninstall
+  "${CMAKE_COMMAND}" -P "${CMAKE_CURRENT_BINARY_DIR}/cmake_uninstall.cmake")
+
diff --git a/CMakeModules/cmake_uninstall.cmake.in b/CMakeModules/cmake_uninstall.cmake.in
new file mode 100644
index 000000000..3b6a9d03c
--- /dev/null
+++ b/CMakeModules/cmake_uninstall.cmake.in
@@ -0,0 +1,22 @@
+IF(NOT EXISTS "@CMAKE_CURRENT_BINARY_DIR@/install_manifest.txt")
+    MESSAGE(FATAL_ERROR "Cannot find install manifest: \"@CMAKE_CURRENT_BINARY_DIR@/install_manifest.txt\"")
+ENDIF()
+
+FILE(READ "@CMAKE_CURRENT_BINARY_DIR@/install_manifest.txt" files)
+STRING(REGEX REPLACE "\n" ";" files "${files}")
+
+FOREACH(file ${files})
+    MESSAGE(STATUS "Uninstalling \"${file}\"")
+    IF(EXISTS "${file}")
+        EXEC_PROGRAM(
+            "@CMAKE_COMMAND@" ARGS "-E remove \"${file}\""
+            OUTPUT_VARIABLE rm_out
+            RETURN_VALUE rm_retval
+            )
+        IF(NOT "${rm_retval}" STREQUAL 0)
+            MESSAGE(FATAL_ERROR "Problem when removing \"${file}\"")
+        ENDIF()
+    ELSE()
+        MESSAGE(STATUS "File \"${file}\" does not exist.")
+    ENDIF()
+ENDFOREACH()
diff --git a/src/Scripting/NasalSys.cxx b/src/Scripting/NasalSys.cxx
index 72c964c04..158d852e5 100644
--- a/src/Scripting/NasalSys.cxx
+++ b/src/Scripting/NasalSys.cxx
@@ -186,8 +186,16 @@ static naRef f_getprop(naContext c, naRef me, int argc, naRef* args)
     case props::BOOL:   case props::INT:
     case props::LONG:   case props::FLOAT:
     case props::DOUBLE:
-        return naNum(p->getDoubleValue());
-
+        {
+        double dv = p->getDoubleValue();
+        if (osg::isNaN(dv)) {
+          SG_LOG(SG_GENERAL, SG_ALERT, "Nasal getprop: property " << p->getPath() << " is NaN");
+          naRuntimeError(c, "getprop() would have read NaN");
+        }
+        
+        return naNum(dv);
+        }
+        
     case props::STRING:
     case props::UNSPECIFIED:
         {
@@ -234,6 +242,11 @@ static naRef f_setprop(naContext c, naRef me, int argc, naRef* args)
             naRef n = naNumValue(val);
             if(naIsNil(n))
                 naRuntimeError(c, "setprop() value is not string or number");
+                
+            if (osg::isNaN(n.num)) {
+                naRuntimeError(c, "setprop() passed a NaN");
+            }
+            
             result = props->setDoubleValue(buf, n.num);
         }
     } catch (const string& err) {
diff --git a/src/Scripting/nasal-props.cxx b/src/Scripting/nasal-props.cxx
index 9f309903a..0ea341b08 100644
--- a/src/Scripting/nasal-props.cxx
+++ b/src/Scripting/nasal-props.cxx
@@ -169,7 +169,16 @@ static naRef f_getValue(naContext c, naRef me, int argc, naRef* args)
     case props::BOOL:   case props::INT:
     case props::LONG:   case props::FLOAT:
     case props::DOUBLE:
-        return naNum((*node)->getDoubleValue());
+    {
+        double dv = (*node)->getDoubleValue();
+        if (osg::isNaN(dv)) {
+          SG_LOG(SG_GENERAL, SG_ALERT, "Nasal getValue: property " << (*node)->getPath() << " is NaN");
+          naRuntimeError(c, "props.getValue() would have read NaN");
+        }
+        
+        return naNum(dv);
+    }
+    
     case props::STRING:
     case props::UNSPECIFIED:
         return NASTR((*node)->getStringValue());
@@ -217,7 +226,13 @@ static naRef f_setValue(naContext c, naRef me, int argc, naRef* args)
         naRef n = naNumValue(val);
         if(naIsNil(n))
             naRuntimeError(c, "props.setValue() with non-number");
-        result = (*node)->setDoubleValue(naNumValue(val).num);
+            
+        double d = naNumValue(val).num;
+        if (osg::isNaN(d)) {
+          naRuntimeError(c, "props.setValue() passed a NaN");
+        }
+        
+        result = (*node)->setDoubleValue(d);
     }
     return naNum(result);
 }
@@ -250,8 +265,13 @@ static naRef f_setDoubleValue(naContext c, naRef me, int argc, naRef* args)
 {
     NODEARG();
     naRef r = naNumValue(naVec_get(argv, 0));
-    if(naIsNil(r))
+    if (naIsNil(r))
         naRuntimeError(c, "props.setDoubleValue() with non-number");
+        
+    if (osg::isNaN(r.num)) {
+      naRuntimeError(c, "props.setDoubleValue() passed a NaN");
+    }
+        
     return naNum((*node)->setDoubleValue(r.num));
 }