someone can help me c++ runtime err ?

plz,
my server Machine is 8G ram

when i open one map - china , gameserver.exe runs OK;
but ,when i open 6 map ,then ram use 4G . pop up c++runtime err .

how can i solve the question ?
------
8G ram only use 4G ram,and only open china ?

plz ,help!

plz ,help! ~~~~~~~~~~~~