Plasterboard walls are lightweight partition walls and NOT made for strong loads. In order to assembly a hammock on such a wall you have to create a separate fixing system using a jamb or a pole before you plank the 2nd side the platerboard wall. The same technique is often realised in e.g. bathrooms for the wash-bowl (basin).
Unfortunately, this is - ex post - quite laborious.
Please ask a professional. Perhaps you come up with a new idea or an alternative solution! For example, you could mount a pole on the wall, or use a wood stick between the mounting points of a hammock or simply use the ceiling for the assembly of your hammock...
