If an fx has its "shader" tag set to "additive" (Shader = ADDITIVE), black is counted as transparency so you'll probably want to make a new fxparticlesystem and change that to ALPHA. Then add the alpha values (alpha = defaultalpha, alpha1, alpha2) to make the effect visible. The number after the rgb value would be transparency.
I haven't used particle systems that much so somebody else would probably be better at explaining this.
it is still a little bit bugged or stranged looking, because you see everywhere black squares instead of one "Word of Power Wave" but i think now i will get this done!
thank you a lot.