Sherlock said:You are pasting it where your avatar goes.
You need to paste the url etc into the box that says
Signature:
This is a block of text that can be added to posts you make. There is a 450 character limit
You are going to far down the page and putting it at the bottom where you avatar (much smaller pic) needs to go. Delete it from there and go back up the page till you see the bigger text box.