pwm library producing errors

I found the following code by Runnerup. It's a library to manipulate pwm frequencies.
I've used it before with success on the same Nano r3. Arduino 1.6.1 on a Macbook running os x 10.6.8. It ran fine on earlier versions of the IDE.

I imported it as a zip file, after renaming it to an acceptable form, and all went well until I attempted to run it, when I received the following error:

In file included from pwmFan25k.ino:1:0:
/Users/mihaisofti/Documents/Arduino/libraries/ArduinoPWMLibv_05/PWM.h:36:33: fatal error: utility/BTimerDefs.h: No such file or directory
#include "utility/BTimerDefs.h"

This is the code:

#include "PWM.h"

int32_t frequency =3000; //frequency in Hz

void setup()
{
  InitTimersSafe();
  bool success = SetPinFrequencySafe(9, frequency);
  if(success) {
    pinMode(13, OUTPUT);
    digitalWrite(13, HIGH); //to show that all's well by lighting led13
  }
}

void loop()
{
  int sensorValue = analogRead(A0);
  pwmWrite(9, sensorValue / 4);
  delay(30);
}

I've tried moving BTimerDefs.h up the hierarchy from '/utility' up one level and changing the path accordingly. I've tried entering #includeBTimerDefs.h at the top, but continue to get the same error.

Can anyone see what's wrong, and could it be changes in the way things should be done in IDE 1.6.1?

Any and all help would be hugely appreciated,

Mihai

I imported it as a zip file

From where?

Can anyone see what's wrong

Without seeing a link to the library? No.

it helps to include it as well

#include "PWM.h"
#include "utility/BTimerDefs.h"

then it should be ok - it works by me