WARNING: Category '' in library ArduinoUnit is not valid. Setting to 'U

To calculate the speed at anemometer WH1080 use this script. When compiling But I get the error. Unfortunately I do not know why.
Help anyone?

speedwind = 0;
counter = 0;
attachInterrupt(0, addcount, CHANGE);
unsigned long millis();
long startTime = millis();
while(millis() < startTime + period) {
}
detachInterrupt(0);

There are no scripts in C/C++. Only code or source code.

OK, here is my entire code:

#include <Arduino.h>
#define AN 2 // příjem z anemometru (digital D2)

// definice konstant měření větru
const float pi = 3.14159265; // číslo pí
int period = 1000; // Measurement period (miliseconds)
unsigned int Sample = 0; // Sample number
unsigned int counter = 0; // B/W counter for sensor
unsigned int RPM = 0; // Revolutions per minute
int anemo = 91; // konstanta pro výpočet rychlosti větru

// proměnné
float speedwind = 0; // rychlost větru (m/s)
float vitr = 0; // rychlost větru km/h

void setup()
{
// nastavení pinů
pinMode(2, INPUT); // pin anemometru vstup
digitalWrite(2, HIGH); // pull up na pinu anemometru
}

// hlavní smyčka
void loop()
{
speedwind = 0;
counter = 0;
attachInterrupt(0, addcount, CHANGE);
unsigned long millis();
long startTime = millis();
while(millis() < startTime + period) {
}
detachInterrupt(0);

RPM=((counter/2)*60)/(period/1000); // Vypocet poctu otacek za 1 minutu
speedwind = ((2 * pi * anemo * RPM)/60) / 1000; // vitr v m/s
vitr = speedwind * 3,6; // vitr v km/h

// vypiseme
Serial.print(speedwind);
Serial.println(" m/s");
Serial.print(vitr);
Serial.println(" km/h");
Serial.print(RPM);
Serial.println(" otacek za minutu");

delay(10000);
}

void addcount()
{
counter++;
}

But I get the error.

What error would that be ?

The only “error” that I get is

Sketch uses 5,116 bytes (15%) of program storage space. Maximum is 32,256 bytes.
Global variables use 246 bytes (12%) of dynamic memory, leaving 1,802 bytes for local variables. Maximum is 2,048 bytes.

Using IDE 1.5.6-r2 and Windows 7

variables used by intr.routine must be declared volatile.
I'd take another look on where to use float instead of ints

But I get the error.

The “error” that says “WARNING: Category ‘’ in library ArduinoUnit is not valid. Setting…”?

Can’t you tell the difference between a warning and an error? Even when the compiler TELLS you it is a warning?