Change "_filename" to "_identifier" for carrierwave

app/models/design/theme.rb

@@ -7,7 +7,7 @@ class Theme < Stylesheet
   protected
   
   def set_name
-    self.name = File.basename(self.file_filename,".css")
+    self.name = File.basename(self.file_identifier,".css")
   end
   
 end