I was fishing in my garrison as well with autoangler. You do need fishing hut to actually fish anything up usable but it works. Oh, I almost forgot - I had to disable pools but it stood there and worked well.
Confirm. In "BotConfig" I set 'poolfishing FALSE' (I did not touch anything more), sit on log and pressed 'Start'. Now when I write here, my toon is fishing in my garrison
Good luck, fishermen!