Problem with hotkey: command+control+option+delete

I had a hotkey set up as command+control+option+delete but for some reason KBM won't accept this for the same macro after mistakenly deleting that hotkey combination.

Is there any reason KBM would prohibit this combination? I cannot find a duplicate hotkey, but that shouldn't matter, since KBM does permit duplicates (it's not advised, but it can happen in error).

Thanks.

If you assign a hotkey to two macros, pressing it will open the conflict palette, so you'd know about it. I don't know the answer to why your key combo isn't working but I can tell you it isn't that.