You may find that the lights go off, but the exposure is still dark. That's the preflash thing that was mentioned a few posts up. If you can't disable ETTL, and can't set the strobes to ignore the preflash, you'll need to get the cord working.
If they are anything like this Adorama slave flash (they certainly seem very similar), They do NOT get activated by the pre flash.
http://www.adorama.com/LTACMS.html![]()
To the OP: The kit says that it comes with 2 PC cords. Did you try the other one?

