Arduino is not responding at uploads

Development Tools IDE 1.x
1

Hi all,

I received my brand new arduino uno.

Connected it to my PC. Installed the drivers on COM7, plugged the usb connector to the arduino board, and tried to upload the blink script.

So i tried the same with my MAC,used different cables. No chance to upload anything. After I read 1000 Forum treads I saw that I could enable the logging of the Upload. This shows me this:

Binäre Sketchgröße: 1.084 Bytes (von einem Maximum von 32.256 Bytes)
/Users/michael/Desktop/Arduino.app/Contents/Resources/Java/hardware/tools/avr/bin/avrdude -C/Users/michael/Desktop/Arduino.app/Contents/Resources/Java/hardware/tools/avr/etc/avrdude.conf -v -v -v -v -patmega328p -carduino -P/dev/tty.usbmodem621 -b115200 -D -Uflash:w:/var/folders/fc/xpcr8lg96sj0017f4wlxfj800000gn/T/build8182471167884275765.tmp/Blink.cpp.hex:i

avrdude: Version 5.11, compiled on Sep 2 2011 at 18:52:52
Copyright (c) 2000-2005 Brian Dean, http://www.bdmicro.com/
Copyright (c) 2007-2009 Joerg Wunsch

System wide configuration file is "/Users/michael/Desktop/Arduino.app/Contents/Resources/Java/hardware/tools/avr/etc/avrdude.conf"
User configuration file is "/Users/michael/.avrduderc"
User configuration file does not exist or is not a regular file, skipping

Using Port : /dev/tty.usbmodem621
Using Programmer : arduino
Overriding Baud Rate : 115200
avrdude: Send: 0 [30] [20]
avrdude: Send: 0 [30] [20]
avrdude: Send: 0 [30] [20]
avrdude: ser_recv(): programmer is not responding
avrdude: stk500_recv(): programmer is not responding

avrdude done. Thank you.

Any Ideas how to fix? It seems that the boot loader is not responding.

Regards
Michael

2

(deleted)

3

Power LED is on.
Loopback is okay.
I tried reseting the arduino before uploading but it did not work again...
Also tried this with reset button on a breadboard.
RX is flashing 3 times when uploading.