SureAI

I wonder if I have a bug in my game.
I found the painting of the tresure map, so now I am looking for the tresure. The tresure is on one of the two island in the lake west of Tirin Abbey right?
And there is two islands on that lake, the tresure is on the south island?
But I have been looking around there, but can not find the tresure, can anybody please tell me exactly where it should be, and what it looks like?
If I do not manage to do this quest is that going to be a problem? I have done several other quests now, I have choosen my star sign, but not my class yet, when can I choose my class?

Haha, I found it, 1 minute after I posted here, that god damned tree

I've spent over an hour searching the island. I found the strength plant but I cannot find the dagger anywhere. Could someone please tell me EXACTLY where I need to look?

[+]

Look at the trees!

Believe me, I've tried that, and nothing is there.

Don't look at the trees with your own eyes, look at the trees with the cross hair, so you can then select something in the tree.

I have a strange problem with this quest. There is just nothing in a chest. I opened every single container in the house, looked in chets where green arrow leads, no drawing and no quest updates. Is it a bug?

ps/ never mind, just found the answer on forum. Had to check inventory..