i was copying and pasting it into the text box that said www. but it is actually the very top box that u first come too that you paste the code into (one with smiley faces etc)then press preview and then save. Took me ages to figure it out as mine kept sayin invalid file too and I just tried the top box out of desperation, and it worked, lol.
Okay, I must be a dunce!! I followed bambi's advice and pasted into' the signature part (as I too was pasting into the url line!!) but it's not the picture of the ticker that's coming up, instead it's a link to it... HELP.. thanks guys