Screen filled in lines

[Vaelfar]

Hi there everybody,
I just installed the client and I tried to play four or five times, but I always get the screen filled in lines; the first time, selecting the realm, I got that bug. The next time I could have choose the realm, but it got stuck the next page... there's a video problem, but don't know what the heck to do... It goes bot for fullscreen and windowed.
Any help?

edit:
I forgot to say that: I'm on the last updated ubuntu... I just installed the client, do I have to install something else?
ps: now it stops by the confirming realm window, I choose the realm and then I just see lines, some sort of description of the realm I cannot read cause of the lines and Confirm or Back. Clicking Confirm doesn't help: I've got to choose the race, but all the backgrond is lined... and even the Molok [if I read right] character is lined, but not the other two.
Sorry for my english, I even got nervous.

second edit:
there's a screenshot of what I got