Thank you. I was able to resolve the issue by uninstalling the program, clearing up any related folders and registry entries and installing from scratch.
If the toolbar the Delete button is on had the button removed, or the whole toolbar was turned off, that would explain what you saw before.
(There is an option for each toolbar to enable its hotkeys even when it's not open, but if that's off for a toolbar that's also no longer present in the window, then the hotkeys from that toolbar won't do anything.)