Yes, install those FTDI drivers first.
Basically the right ZIm board is nothing more than an Arduino Board with routed pins for the stepper motors - if you have problems connecting you can also have a look at people having issues on Arduino connection at Google.
After installing (maybe rebooting too?) start Repetier Host and find your serial connectrion (I usually have 2 and one of them is the right one) and enter 250.000 baud for the speed: connect (or try the other serial connector) and you’re free to play without any limitations
-> don’t forget to unplug the left electronic board (the ZIMboard with the dual USB ports on top) complety from the right borad: unplug the two cables!!)