nth rule problems

i am following the guide http://wiki.mikrotik.com/wiki/Load_Balancing_Persistent to play with load balancing with multiple services. I get an error when it comes to the lines of code dealing with nth:

invalid value for counter, an integer required

What am I doing wrong? I played with the values in the GUI of winbox, but don’t quite get it.

it means that all nth option values must be integers, you can’t set for example 0.3 or something like that.