problem with plasterboard wall!!

[spanky]

I have had two kitchen cabinets up on the wall for nearly a year when they decided to crash to floor spilling the entire contents.

The walls are plasterboard, with about a 4" gap behind before the brick wall.
What are the best fixings to use?
I initially used the metal ones that open up when screwed in but all they do is tear up the plasterboard and then just hang loose.

Would it be ok to use really long ones that can go through the plasterboard and into the brick?

need help with this somebody suggest what would be the right fixing?
Thanks

[welsh brickie]

Use stardrive fixings long enough to fix into the wall behind,no plugs are required.