Code:
starting template download from: http://download.proxmox.com/images/system/centos-6-default_6-20150619_amd64.tar.gz
target file: /var/lib/vz/template/cache/centos-6-default_6-20150619_amd64.tar.gz
converted 'http://download.proxmox.com/images/system/centos-6-default_6-20150619_amd64.tar.gz' (ANSI_X3.4-1968) -> 'http://download.proxmox.com/images/system/centos-6-default_6-20150619_amd64.tar.gz' (UTF-8)
--2014-11-18 09:05:06-- http://download.proxmox.com/images/system/centos-6-default_6-20150619_amd64.tar.gz
Proxy request sent, awaiting response... 404 Not Found
2014-11-18 09:05:06 ERROR 404: Not Found.
TASK ERROR: download failed - Resource temporarily unavailable
seem a URL typo