Sorry if I was unclear. I typically do the same. When I mouse-over that contact link to the left of a HIT, the words "Contact this Requester" appear. [Edit] Sorry, this reply isn't clear either ... see below.
Oh, sorry. I didn't realize it said that. I thought that was when you clicked on CastingWords in the list of HITs you had. You can also email them at turkers@castingwords.com : )
Sorry, my previous reply was poorly written. To clarify: When I click "Your Account", and then click a date under "Your HIT Status" to see my completed HITs for that date, and then mouse-over a requester's name in that list, then the words "Contact this Requester" appear in a little yellow pop-up box ('tooltip').