Opening two Processes fails

My niece plays this game everyday
http://game.zing.vn/boom/download/boom.html

After she runs the game and logs in with her created username and password

she tries run that game process again but the downloaded screen stops with an error message that "the same process has been running/opening, please close it and retry".

How is it possible to then run two or more of this game's processes at the same time ? Thank you

It sounds like the game server doesn't allow you to have more than one active session. If so it's not much you can do about it.