If you're alt-tabbing, you're doing it wrong. WoW should only be run in windowed mode, not fullscreen. Then the keys can pass to both windows.

I'd suggest going to the HotKeyNet tutorial link in my sig and starting from scratch. Then if you're still having issues, post the details, including the errors and the script you are using so that I can troubleshoot what's not working.

After you have the basic broadcasting working, then we can work on editing the script to do specific things.