Math lib problem

Hello, i am having problems with math library using energia. I always keep getting thi s error. I dont know whats wrong.

Error  : http://pastie.org/8127090

Here you can read the source : http://pastie.org/8127093#871-872

I highlighted the lines which are makeing troubles. Its lines 871 and 872, by commenting them you can avoid getting this error.

float accel_angle_y = atan(-1*accel_x/sqrt(pow(accel_y,2) + pow(accel_z,2)))*RADIANS_TO_DEGREES;
float accel_angle_x = atan(accel_y/sqrt(pow(accel_x,2) + pow(accel_z,2)))*RADIANS_TO_DEGREES;