When selecting a quest item to use from the objective tracker, I receive the error "QuestPointer has been blocked from an action only available to the Blizzard UI".

I am using QuestPointer v31.

Two quest items I have tried are those from 'Carp Care', and 'The War Within'

That seems to have fixed it for me, at least.

Great, thanks for the fix!
I've tested the new version on another couple of quests with items with no issues.
Cheers