Change in game name

I want to change the name, enter a new and wrote me this: Please ensure there's no space, and use only Alpha Numeric characters and _-[]*. What is it? what's the problem?
Nick which I'm typing: tAS.eXe...?

That profile of my friend, he changed his nickname 3 hours ago http://clan.z8games.com/charstat_cf.aspx?usn=4959864, pay attention to his nickname nWG.eXe ...? , "?" there is also used, here is my old nickname [Rus] koljA?