Error: The event 'onDisplay' does not exist!是什么意思

Error: The event 'onDisplay' does not exist!是什么意思 Error:Traffic policy does not exist Filesystem error (2):File or directory does not exist "ERROR:42P01:table \"q_temptable1\" does not exist" The specified directory does not exist the index ’GetTodayRandom’does not exist The password you provided does not exist! user does not exist Does not exist Perfection does not exist Index does not exist D:\c++\Cpp1.cpp(2) : error C2871: 'std' : does not exist or