Im making a list with some sub-skills for a game and need to instance the cSS this is what i have:

cSS[] subskill = new cSS[5];
subskill[0] = cSS(id, name, effect, bought, cost);

But the compiler doesn't like my code, why?

cSS[] subskill = new cSS[5];

This allocate only memory for Array object subskill not for its elements. So you need to allocate memory for each elements.

subskill[0] = cSS(id, name, effect, bought, cost);

Instead
use subskill[0] = new cSS(id, name, effect, bought, cost);