There has been plenty of discussion on this topic before - do some searches on "plasterboard" or "stud wall" or similar and you should find lots of info. Basically, if it's a internal frame/plasterboard wall then you will need to mount on the wooden framework rather than the plasterboard or add some more framework to support the plasma.
Thanks I already did a search under plasterboard, but the other search provided more results thanks. Phoned a guy who's good at this stuff and he said he's fitted kitchen cupboards that weighed more onto plasterboard! He uses special screws or something!
Mines on plasterboard with 2 of the eight fixings through metal stud. The fixings are from B and Q and one is able to support about 15-20kg in 9mm plaster board. It is ROCK SOLID.
Bear in mind though that mine is a wall that has 18mm of plasterboard. Best thing to do is put bracket up and hang 30 odd kg from it. Doesn't worry me at all.
mine is on the platerboard wall too , with all 12 holes filled with those fixings above , i hung my fat little body off it with my arms and i weigh more than 28kg i am sorry to say and it is SOLID so i can recommend them
Drywall, plasterboard, gypsum etc etc. Good for walls, poor for hanging stuff from. Especially with modern building techniques where only a few "drywall" screws are used rather than 40/60 nails.
All is not lost though! You just need to mount on to what the drywall is mounted on to! You could have metal studs, or more traditional wood. New "traditional" build houses use dob and dab, where a few dolops of plaster hold the drywall to the inner brick. Again, need to mount to the brick rather than the drywall.
The builder of the house I'm in has a motto "Better build houses". I'd like to know, better than whom? I wouldn't trust hanging my plasma on the drywall here. Infact, even the toliet roll holders fell off....