Unable to connect console exit ..exit code 2

Hi,
I try to use console on my fresh proxmox set up but :
Error: command 'bin/nc -l -p 5900 -w 10 -c 'usr/sbin/qm vncproxy 100 2 > /dev/null" failed: exit code2

- Proxmox VE Version : 3.0-20/0428106c
- Java : Version 7 Update 25
my Windows 7 Laptop firewall is disabled
I used Firefox, IE and chrome

Thanks for you comments