the game will be crashed when I place wards.

I have been played in NA for few weeks, and I have found the game will crash if I place a ward in the game and I have to log out and reconnect the game again. it has been the 6th time today that i have to reconnect because of the game crash. this kind of problems will happens as soon as I place PINK WARDS , and SOMETIMES it will happen if I place ORIGINAL wards like . however, it won't happen if i use or . hope someone could help me to finger out whats the problem of place the ward, because it really cause big problems if I don't place wards or reconnect the game.