diff --git a/Modules/_tkinter.c b/Modules/_tkinter.c
index bf7501e..fc52657 100644
--- a/Modules/_tkinter.c
+++ b/Modules/_tkinter.c
@@ -514,7 +514,7 @@
 	ckfree(argv0);
 
 	if (Tcl_AppInit(v->interp) != TCL_OK)
-		return (TkappObject *)Tkinter_Error(v);
+		return (TkappObject *)Tkinter_Error((PyObject *)v);
 
 	EnableEventHook();