Vielen Dank erstmal. Letzter Versuch
Habe die Kommandozeile wie folgt geändert:
avrdude -pm328p -cstk500v1 -PCOM6 -b57600 -D -Uflash:w:G:\UserDaten\Willi\Documents\Programmieru ng\Arduino\workspace\Hello_Blink\Hello_Blink.hex:i

Code:
/*
 * main.c
 *
 *  Created on: 18.04.2010
 *      Author: Willi
 */

#include "WProgram.h"

// prototypes
void blink(int n, int d);

// variables
int ledPin = 13; // LED connected to digital pin 13

extern "C" {
  void __cxa_pure_virtual()
  {
    // put error handling here
  }
}



void setup(){
Serial.begin(9600);	// opens serial port, sets data rate to 9600 bps
pinMode(ledPin, OUTPUT);      // sets the digital pin as output
Serial.println("------------------");
Serial.println("   hello world");
Serial.println("------------------");
}

void loop(){

  blink(3, 1000); // blink led (n times, ms interval)
  delay(5000); // wait 1 sec
}

void blink(int n, int d){
  for (int i=0; i<n; i++) {
    digitalWrite(ledPin, HIGH);
    delay(d/2);
    digitalWrite(ledPin, LOW);
    delay(d/2);
  }
}

int main(void)
{
init();

setup();

for (;;)
loop();

return 0;
}
Die Fehlermeldung lt.
---
**** Build of configuration Debug for project Hello_Blink ****

make all
Invoking: Print Size
avr-size --format=avr --mcu=atmega328p Hello_Blink.elf
AVR Memory Usage
----------------
Device: atmega328p

Program: 8184 bytes (25.0% Full)
(.text + .data + .bootloader)

Data: 482 bytes (23.5% Full)
(.data + .bss + .noinit)


Finished building: sizedummy

Invoking: AVRDude
C:\WinAVR\bin\avrdude -pm328p -cstk500v1 -Pavrdude -pm328p -cstk500v1 -PCOM6 -b57600 -D -Uflash:w:G:\UserDaten\Willi\Documents\Programmieru ng\Arduino\workspace\Hello_Blink\Hello_Blink.hex:i -Evcc -Uflash:w:Hello_Blink.hex:a
avrdude: WARNING: -E option not supported by this Programmer type
avrdude: stk500_getsync(): not in sync: resp=0x00

avrdude done. Thank you.

make: *** [avrdudedummy] Error 1
---

Das Projekt ist in Eclipse angelegt. Die .hex Dateil liegt im Debugverzeichnis. Meine Versuche habe ich übrigens mit dem [EP-Wiki] von Burli unternommen.
VG
Willi