Traytip does not appear in Windows 2000 Pro SP4. Tested with AutoHotkey 1.1.05.06 Unicode x32, and R53 (the oldest one I have). However, it works with Basic.
#persistent TrayTip, TrayTip Sample, This will be displayed for 5 seconds., 5, 1
I did not find this value on Windows 2000. So I created it and set it to 1 and rebooted the machine and ran the script but traytip does not appear. Basic works even it is set to 0.
HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced >> EnableBalloonTips