cueing

I have bought a Griffin DJ cable but it doesn’t work on My Macbook pro 10.6 and each time i click on the headphones symbol I get a drop down box saying ‘In order to pre-listen to music, you can use headphones through USB or an external sound card.’ I’ve wasted money on this lead and now do not want to waste more so has anybody any suggestions of a piece of kit that might allow me to cue and mix as I would on 2 CDJ’s and a mixer ?
chris

Split-output is only supported in the latest version - djay 4. If you have this version, please click on the headphones button at the bottom right corner of the screen and select “Split-Output” for pre-cueing.

doesnt work guys