Trouble extracting object

I'm trying to extract a simple object from a white background. After I highlight the object I am not able to click on "preview" or "ok" but only cancel. Can you tell me what I'm doing wrong?

John

i'm not sure if this is it, but after highlighting the object, did you fill it in with the paintbucket tool? after that you should be able to preview/ok it. (i'm at work now, so i can't test it out for you)

you're right, that did the trick. I never would have guessed it.

thank you so much,
John