problems with static when monitoring a track.

hope someone can shed some light on this problem…

I’ve installed Cubase LE6 on my iMAC, along with the Komplete Audio 6 interface, which I bought in the same package.
Both seem to have been installed properly, but when I open up a project on Cubase, select a track, and press the monitor button I get nothing but static.
VST connections seem to be set up properly, as per the start up manual.
The interface works fine when not going through Cubase (i.e., when using iTunes etc)
I’ve tried changing the latency, under devices - select driver- control panel etc, to no avail.

As a side point, the metronome also started doing funny things when I changed the tempo / signature

Do I have a load of bugs in the system? Any ideas?