VMR-MDK, xterm Can't open display

[sslx]

While VMR-MDK is running, it throws tons of the following error:
xterm: Xt error: Can't open display: %s
How can I fix it?
I'm using Odroid c1+, and running kali-2.1.2-odroidc.img.
Thanks

[sslx]

Fixed. I needed to enable x11 forwarding in putty.