The window you're seeing may be the custom window you installed from eq2interface. If it's not working for you, I recommend removing it for now. Check the checkbox for
Options > User Interface > Game Windows > Show Autoattack Bar
And see if that works. Get into combat with a melee weapon and the bar should match the one on the DarqUI Threat window. If you're seeing the large default window but not the bar, try resizing the window taller.
Incidentally, the DarqUI autoattack bars have an audible signal that you might like to use for timing your attacks along with the default autoattack window. Open the window manager to the Threat page and click the button at the bottom. If you like the sound but not the bars, disable the bars and enable the audible.
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