[Mitchell]

Maybe if you actually defined all the values you're realize the fxTime is at 6 seconds by default and you're displaying it only for 2.0 seconds, which means it's probably there you just can't see it.

SetHudTextParams(float x, float y, float holdTime, int r, int g, int b, int a, int effect = 0,
float fxTime=6.0, float fadeIn=0.1, float fadeOut=0.2);

try this:
SetHudTextParams(-1.0, 0.45, 10.0, 255, 235, 20, 200, 1, 0.0, 0.0, 0.0);