diff --git a/modules/core_lib/util.lua b/modules/core_lib/util.lua
index f231b902..23234de7 100644
--- a/modules/core_lib/util.lua
+++ b/modules/core_lib/util.lua
@@ -79,7 +79,6 @@ end
 
 local oldtonumber = tonumber
 function tonumber(v)
-  local v = oldtonumber(v)
-  if not v then return 0 end
-  return v
+  if v == nil then return 0 end
+  return oldtonumber(v)
 end
diff --git a/src/framework/luascript/luavaluecasts.cpp b/src/framework/luascript/luavaluecasts.cpp
index cb9065ee..352a4b6b 100644
--- a/src/framework/luascript/luavaluecasts.cpp
+++ b/src/framework/luascript/luavaluecasts.cpp
@@ -45,8 +45,8 @@ void push_luavalue(int i)
 bool luavalue_cast(int index, int& i)
 {
     i = g_lua.toInteger(index);
-    //if(i == 0 && !g_lua.isNumber(index))
-    //    return false;
+    if(i == 0 && !g_lua.isNumber(index) && !g_lua.isNil())
+        return false;
     return true;
 }
 
@@ -59,8 +59,8 @@ void push_luavalue(double d)
 bool luavalue_cast(int index, double& d)
 {
     d = g_lua.toNumber(index);
-    //if(d == 0 && !g_lua.isNumber(index))
-    //    return false;
+    if(d == 0 && !g_lua.isNumber(index) && !g_lua.isNil())
+        return false;
     return true;
 }