diff --git a/owilix/core/duckdb.py b/owilix/core/duckdb.py
index ce50817..1c59764 100644
--- a/owilix/core/duckdb.py
+++ b/owilix/core/duckdb.py
@@ -529,7 +529,7 @@ class OWIDuckDBCopy (OWIDuckDBSelect):
         if batch_size <= 0:
             batch_size = self.batch_size
         conn, temp_dir = None,  tempfile.TemporaryDirectory()
-        _error=None
+        _error, _sub_path = None, None
         try:
 
             # Path for the temporary database file