Hi,
a 2d vector rotation is computed as follows

Code:
x1 = x * cos - y * sin;
y1 = x * sin + y * cos;


Anyway, the computation of the offset vector should not be performed each frame. Otherway it will continuously lose a little length caused by the accuracy limits of the variables.

Code:
vec_diff(my.skill1, my.x, entParent.x); // save the offset vector into three skills
while(1) {
   vec_set(my.x, my.skill1);
   vec_rotate(my.x, entParent.pan);
   vec_add(my.x, entParent.x);
   vec_set(my.pan, entParent.pan);
   wait(1);
}


Salud!