Using List boxes and Combo Boxes in Ruby on Steel

I have just started using Ruby on Steel to create GUI

When I simply drag and drop a list box and add some items in the Form
and then
click Ruby Run Menu, I get the following error message

:0:in InitializeComponent': wrong number or type of arguments forAddRange’ (ArgumentError)
from Snippets:0:in main' from Snippets:0:inInitialize’

Can anyone please help me how to solve the problem

Thanks,
navin