Network Simulator

Hi!

I would like to practice with routerOS before I start working with it in real life.
I’m trying to emulate routerOS following this guide:
http://www.slideshare.net/ropix/mikrotik-network-simulator-mum-presentation-material-2013

Unfortunately QEMU gives the following error message: “Couldn’t read from CDROM”.
I’m not sure if I’ve used the right file (routeros-x86-6.26rc20.npk). The guide was using .img file but I thought it should work with .npk too.

Could you help me out here please? I’m a bit confused.