I can't seem to reply to your last message for some reason, but I am aware of the timer ID issue and I did try several different values for wParam and lParam even before my initial post. None of them seemed to be any more effective than using 0, 0, and some even blew up perl, so I left them out of the example. Anyway, I solved the problem by using a different message all together (WM_USER) as is (now) detailed in the OP. Thx.
in reply to Re^3: Win32::GUI sending Windows messages between threads
in thread Win32::GUI sending Windows messages between threads [solved]