fixed Registry event handler object

diff --git a/Interface/AddOns/SVUI/system/classes/Registry.lua b/Interface/AddOns/SVUI/system/classes/Registry.lua
index 7f351a9..364e073 100644
--- a/Interface/AddOns/SVUI/system/classes/Registry.lua
+++ b/Interface/AddOns/SVUI/system/classes/Registry.lua
@@ -118,7 +118,9 @@ local function SetPrototype(obj)
         obj.___eventframe:RegisterEvent(eventname)
     end
     obj.UnregisterEvent = function(obj, event, func)
-        obj.___eventframe:UnregisterEvent(event)
+        if(obj.___eventframe) then
+            obj.___eventframe:UnregisterEvent(event)
+        end
     end
     return obj
 end