Don't try to enable nameplates or forbidden objects

diff --git a/BlizzardFrames.lua b/BlizzardFrames.lua
index a0111f1..bc39126 100755
--- a/BlizzardFrames.lua
+++ b/BlizzardFrames.lua
@@ -162,6 +162,11 @@ function addon:Enable_BlizzCompactUnitFrames()
     end

     hooksecurefunc("CompactUnitFrame_SetUpFrame", function(frame, ...)
+        -- For the moment we cannot handle 'forbidden' frames
+        if frame.IsForbidden and frame:IsForbidden() then
+            return
+        end
+
         local name = frame and frame.GetName and frame:GetName()
         for i = 1, 3 do
             local buff = _G[name .. "Buff" .. i]