diff --git a/stepmania/Themes/default/BGAnimations/_frame 3x1/default.lua b/stepmania/Themes/default/BGAnimations/_frame 3x1/default.lua
index 05d7a8d023..85a71d6b86 100644
--- a/stepmania/Themes/default/BGAnimations/_frame 3x1/default.lua	
+++ b/stepmania/Themes/default/BGAnimations/_frame 3x1/default.lua	
@@ -1,4 +1,7 @@
 local File, Width = ...
+assert( File );
+assert( Width );
+
 local FullFile = THEME:GetPathB('','_frame files 3x1/'..File )
 local Frame = LoadActor( FullFile )
 
diff --git a/stepmania/Themes/default/BGAnimations/_frame 3x3/default.lua b/stepmania/Themes/default/BGAnimations/_frame 3x3/default.lua
index 07db367cc3..a3a28fc56f 100644
--- a/stepmania/Themes/default/BGAnimations/_frame 3x3/default.lua	
+++ b/stepmania/Themes/default/BGAnimations/_frame 3x3/default.lua	
@@ -1,4 +1,8 @@
 local File, Width, Height = ...
+assert( File );
+assert( Width );
+assert( Height );
+
 local FullFile = THEME:GetPathB('','_frame files 3x3/'..File )
 local Frame = LoadActor( FullFile )
 return WrapInActorFrame {