I may be wrong in this case, but I have seen many automation cases where you must pass a parameter, even if the the parameter value isn't important by itself. Try

upt.Cancel(.T.)

>Visual Studio Object Explorer shows that upt.ocx has Cancel method (image1).
>Visual FoxPro properties do not show this methid (image2)
>
>upt.Cancel() throws error
>
>Property Cancel is not a method or event (image3)
>
>?upt.Cancel() thows error
>
>Invalid subscript reference.
>
>Other methods of this control can called OK.
>Maybe name Cancel is used by FoxPro internally so that method with same name cannot called.
>
>How to call ActiveX Cancel method from FoxPro. I can provide this upt and test VFP code.