A quick fix for those of you who want to use 1.4.1 is just to make that variable a global instead of local Line 1202: local $ok = GUICtrlCreateButton(t('OK_BUT'), 55, 170, 80, 20) Changed to global $ok = GUICtrlCreateButton(t('OK_BUT'), 55, 170, 80, 20) I think the reason it's complaining is that it's being called from a function outside the scope of where the variable is declared.