avr-g++ error

Development Tools IDE 1.x
3

1001100111100:
Hi,
I have the problem that when I try to download anything to my Mega 2560 it says "avr-g++ avr-g++: CreateProcess: No such file or directory" i just downloaded arduino 1.0.1

http://arduino.cc/forum/index.php/topic,118440.0.html <-