I have read through Runnerup's posts, and cannot find a solution to this problem. I copied the code, and have checked and rechecked it, but cannot see any error in the code, or its syntax.
It may be something basic and obvious, but I can't see it, for the life of me.
I would greatly appreciate a pointer. I'm using Arduino 1.6.1. Could this be the problem?
Mihai
#include <PWM.h>
int32_t frequency =30000; //frequency in Hz
void setup()
{
InitTimersSafe();
bool success = SetPinFrequencySafe(9, frequency);
if(success) {
pinMode(13, OUTPUT);
digitalWrite(13, HIGH);
}
}
void loop()
{
int sensorValue = analogRead(A0);
pwmWrite(9, sensorValue / 4);
delay(30);
}[b][/b]
HI,
What model arduino are you compiling it for?
Tom... 
Sorry! it's an arduino nano r3 clone
Hi,
I tried to compile it as UNO, needed to have PWM library.
https://code.google.com/p/arduino-pwm-frequency-library/downloads/detail?name=Arduino%20PWM%20Frequency%20Library%20v_05.zip&can=2&q=
Place the PWM folder into the MyDocument/Arduino/Libraries folder
Then reboot the IDE.
Tom.... 
Well, I've successfully used it before with the same setup, but I will remove it all and try again. I've now done this, and now have different errors. I think it's to do with file locations - what do you think?
/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"
Thanks for the suggestions though.
Mike
The folder containing the offending files were nested inside another folder, so I moved the nested folder up one level, and all is now well.
Thanks for your help Tom
Mike