Assuming Interact with Target in General Key Map is the standard version generated by ISBoxer:
1. This will not work
2. You should not be using a Target of "Window:All w/o Current"

If you want to add IWT, just add a keystroke action that sends your configured IWT key to your melees, and have Click to Move enabled in the interface. The generated IWT mapped key is 2-step so that it can automatically turn CTM back off. When this is done with a Do Mapped Key Action, the second step is performed immediately and may not work. You're saying it mostly works, so you might just need to fix the Target.

About the Target, I have a very in depth post that will probably go way over your head that explains how it works in great detail, but the gist of it is that when you have a Mapped Key that already sends something to multiple toons (such as when you hit your IWT hotkey, or one of the DPS hotkeys), and you want to use it via Do Mapped Key Action, you want to send it to Window:Current so that it works exactly like when you hit your hotkey. Otherwise, it's going to tell each window to do the same thing as pressing your hotkey, meaning that your current window will be instructed to assist each other guy.