healbot addon for tbc HELP

Hi! I have used healbot addon about 10 years ago (!) on tbc 2.4.3. but cannot seem to manage. I have downloaded another vanilla tbc but no joy.

The /hb o gives no errors but interface simply does not load.

It is a useful tool for helping healing in groups as it shows the health bar and you simply click the addon rather than the player than the heal.

I cannot roll a holy pala which is my ambition without such an addon as I could not physically do it with the mouse/keyboard shortcuts.

any help appreciated.

M.