When callvote kick is called though the menus, it does not work correctly if the player has a carret, (a.k.a ^) character in their name. This is likely due to the special significance of the ^ character in generating color codes. For instance if a player sets his/her name to ‘^^ttjw’ the name will draw as ‘^tjw’, and when someone tries to vote to kick that player through the menu, they will get a “Player not on server” message. However, issuing the ‘/callvote kick ^^ttjw’ message will work.
As a fix, I think the menu’s should use the PID (Player ID) number, and the PID number should work for ‘/callvote kick PID’ as well as ‘/rcon kick PID’ which it currently does not.