Enchanting...pls HELP?Follow

Ok, I'm having some major problems with enchanting! Why is it then when I go to ULD to learn new enchants from this vile wench she is NEVER there!? I'm not an idiot - I HAVE THE RIGHT ROOM! I've already been to see her once. I was having this problem before the first time I saw, and now having the same problem. Doe anyone else encounter this aggrevation, or possibly know why it is that I must?? Thanks .. :)