virt-manager doesn't start KVM virtualization RHEL 7

I have installed recently a RHEL for creating a virtual host. I have started from minimal install, and later install with groupinstall the needed goups "Virtualization Tools" " Virtualization Hypervisor" "Virtualization Client" "Virtualization Platform" "Virtualization Tools". I've configured the network with set static IP, and bond with active backup two ethernet interface.
After I tried to start virt-manager I received en error message.
** (virt-manager:16946): WARNING **: Could not open X display Gtk couldn't be initialized

A have started XMING server on a windows 7 workstation and I use putty with enable X11 port forwarding.

I have google the error, but I don't find any answer to my problem,

Szabolcs Sandor