根据报错的数字找原因对应问题出处，如图，报错131，对应到define， ERR_INVALID_TRADE_VOLUME，也就是交易变量有问题。

//---errors returned from trade server

#define ERR_NO_ERROR 0

#define ERR_NO_RESULT 1

#define ERR_COMMON_ERROR 2

#define ERR_INVALID_TRADE_PARAMETERS 3

#define ERR_SERVER_BUSY 4

#define ERR_OLD_VERSION 5

#define ERR_NO_CONNECTION 6

#define ERR_NOT_ENOUGH_RIGHTS 7

#define ERR_TOO_FREQUENT_REQUESTS 8

#define ERR_MALFUNCTIONAL_TRADE 9

#define ERR_ACCOUNT_DISABLED 64

#define ERR_INVALID_ACCOUNT 65

#define ERR_TRADE_TIMEOUT 128

#define ERR_INVALID_PRICE 129

#define ERR_INVALID_STOPS 130

#define ERR_INVALID_TRADE_VOLUME 131

#define ERR_MARKET_CLOSED 132

#define ERR_TRADE_DISABLED 133

#define ERR_NOT_ENOUGH_MONEY 134

#define ERR_PRICE_CHANGED 135

#define ERR_OFF_QUOTES 136

#define ERR_BROKER_BUSY 137

#define ERR_REQUOTE 138

#define ERR_ORDER_LOCKED 139

#define ERR_LONG_POSITIONS_ONLY_ALLOWED 140

#define ERR_TOO_MANY_REQUESTS 141

#define ERR_TRADE_MODIFY_DENIED 145

#define ERR_TRADE_CONTEXT_BUSY 146

#define ERR_TRADE_EXPIRATION_DENIED 147

#define ERR_TRADE_TOO_MANY_ORDERS 148

#define ERR_TRADE_HEDGE_PROHIBITED 149

#define ERR_TRADE_PROHIBITED_BY_FIFO 150

//---mql4 run time errors

#define ERR_NO_MQLERROR 4000

#define ERR_WRONG_FUNCTION_POINTER 4001

#define ERR_ARRAY_INDEX_OUT_OF_RANGE 4002

#define ERR_NO_MEMORY_FOR_CALL_STACK 4003

#define ERR_RECURSIVE_STACK_OVERFLOW 4004

#define ERR_NOT_ENOUGH_STACK_FOR_PARAM 4005

#define ERR_NO_MEMORY_FOR_PARAM_STRING 4006

#define ERR_NO_MEMORY_FOR_TEMP_STRING 4007

#define ERR_NOT_INITIALIZED_STRING 4008

#define ERR_NOT_INITIALIZED_ARRAYSTRING 4009

#define ERR_NO_MEMORY_FOR_ARRAYSTRING 4010

#define ERR_TOO_LONG_STRING 4011

#define ERR_REMAINDER_FROM_ZERO_DIVIDE 4012

#define ERR_ZERO_DIVIDE 4013

#define ERR_UNKNOWN_COMMAND 4014

#define ERR_WRONG_JUMP 4015

#define ERR_NOT_INITIALIZED_ARRAY 4016

#define ERR_DLL_CALLS_NOT_ALLOWED 4017

#define ERR_CANNOT_LOAD_LIBRARY 4018

#define ERR_CANNOT_CALL_FUNCTION 4019

#define ERR_EXTERNAL_CALLS_NOT_ALLOWED 4020

#define ERR_NO_MEMORY_FOR_RETURNED_STR 4021

#define ERR_SYSTEM_BUSY 4022

#define ERR_DLLFUNC_CRITICALERROR 4023

#define ERR_INTERNAL_ERROR 4024//new MQL4

#define ERR_OUT_OF_MEMORY 4025//new MQL4

#define ERR_INVALID_POINTER 4026//new MQL4

#define ERR_FORMAT_TOO_MANY_FORMATTERS 4027//new MQL4

#define ERR_FORMAT_TOO_MANY_PARAMETERS 4028//new MQL4

#define ERR_ARRAY_INVALID 4029//new MQL4

#define ERR_CHART_NOREPLY 4030//new MQL4

#define ERR_INVALID_FUNCTION_PARAMSCNT 4050

#define ERR_INVALID_FUNCTION_PARAMVALUE 4051

#define ERR_STRING_FUNCTION_INTERNAL 4052

#define ERR_SOME_ARRAY_ERROR 4053

#define ERR_INCORRECT_SERIESARRAY_USING 4054

#define ERR_CUSTOM_INDICATOR_ERROR 4055

#define ERR_INCOMPATIBLE_ARRAYS 4056

#define ERR_GLOBAL_VARIABLES_PROCESSING 4057

#define ERR_GLOBAL_VARIABLE_NOT_FOUND 4058

#define ERR_FUNC_NOT_ALLOWED_IN_TESTING 4059

#define ERR_FUNCTION_NOT_CONFIRMED 4060

#define ERR_SEND_MAIL_ERROR 4061

#define ERR_STRING_PARAMETER_EXPECTED 4062

#define ERR_INTEGER_PARAMETER_EXPECTED 4063

#define ERR_DOUBLE_PARAMETER_EXPECTED 4064

#define ERR_ARRAY_AS_PARAMETER_EXPECTED 4065

#define ERR_HISTORY_WILL_UPDATED 4066

#define ERR_TRADE_ERROR 4067

#define ERR_RESOURCE_NOT_FOUND 4068//new MQL4

#define ERR_RESOURCE_NOT_SUPPORTED 4069//new MQL4

#define ERR_RESOURCE_DUPLICATED 4070//new MQL4

#define ERR_INDICATOR_CANNOT_INIT 4071//new MQL4

#define ERR_INDICATOR_CANNOT_LOAD 4072//new MQL4

#define ERR_NO_HISTORY_DATA 4073//new MQL4

#define ERR_NO_MEMORY_FOR_HISTORY 4074//new MQL4

#define ERR_NO_MEMORY_FOR_INDICATOR 4075//new MQL4

#define ERR_END_OF_FILE 4099

#define ERR_SOME_FILE_ERROR 4100

#define ERR_WRONG_FILE_NAME 4101

#define ERR_TOO_MANY_OPENED_FILES 4102

#define ERR_CANNOT_OPEN_FILE 4103

#define ERR_INCOMPATIBLE_FILEACCESS 4104

#define ERR_NO_ORDER_SELECTED 4105

#define ERR_UNKNOWN_SYMBOL 4106

#define ERR_INVALID_PRICE_PARAM 4107

#define ERR_INVALID_TICKET 4108

#define ERR_TRADE_NOT_ALLOWED 4109

#define ERR_LONGS_NOT_ALLOWED 4110

#define ERR_SHORTS_NOT_ALLOWED 4111

#define ERR_OBJECT_ALREADY_EXISTS 4200

#define ERR_UNKNOWN_OBJECT_PROPERTY 4201

#define ERR_OBJECT_DOES_NOT_EXIST 4202

#define ERR_UNKNOWN_OBJECT_TYPE 4203

#define ERR_NO_OBJECT_NAME 4204

#define ERR_OBJECT_COORDINATES_ERROR 4205

#define ERR_NO_SPECIFIED_SUBWINDOW 4206

#define ERR_SOME_OBJECT_ERROR 4207

#define ERR_CHART_PROP_INVALID 4210//new MQL4

#define ERR_CHART_NOT_FOUND 4211//new MQL4

#define ERR_CHARTWINDOW_NOT_FOUND 4212//new MQL4

#define ERR_CHARTINDICATOR_NOT_FOUND 4213//new MQL4

#define ERR_SYMBOL_SELECT 4220//new MQL4

#define ERR_NOTIFICATION_ERROR 4250

#define ERR_NOTIFICATION_PARAMETER 4251

#define ERR_NOTIFICATION_SETTINGS 4252

#define ERR_NOTIFICATION_TOO_FREQUENT 4253

#define ERR_FTP_NOSERVER 4260//new MQL4

#define ERR_FTP_NOLOGIN 4261//new MQL4

#define ERR_FTP_CONNECT_FAILED 4262//new MQL4

#define ERR_FTP_CLOSED 4263//new MQL4

#define ERR_FTP_CHANGEDIR 4264//new MQL4

#define ERR_FTP_FILE_ERROR 4265//new MQL4

#define ERR_FTP_ERROR 4266//new MQL4

#define ERR_FILE_TOO_MANY_OPENED 5001//new MQL4

#define ERR_FILE_WRONG_FILENAME 5002//new MQL4

#define ERR_FILE_TOO_LONG_FILENAME 5003//new MQL4

#define ERR_FILE_CANNOT_OPEN 5004//new MQL4

#define ERR_FILE_BUFFER_ALLOCATION_ERROR 5005//new MQL4

#define ERR_FILE_CANNOT_DELETE 5006//new MQL4

#define ERR_FILE_INVALID_HANDLE 5007//new MQL4

#define ERR_FILE_WRONG_HANDLE 5008//new MQL4

#define ERR_FILE_NOT_TOWRITE 5009//new MQL4

#define ERR_FILE_NOT_TOREAD 5010//new MQL4

#define ERR_FILE_NOT_BIN 5011//new MQL4

#define ERR_FILE_NOT_TXT 5012//new MQL4

#define ERR_FILE_NOT_TXTORCSV 5013//new MQL4

#define ERR_FILE_NOT_CSV 5014//new MQL4

#define ERR_FILE_READ_ERROR 5015//new MQL4

#define ERR_FILE_WRITE_ERROR 5016//new MQL4

#define ERR_FILE_BIN_STRINGSIZE 5017//new MQL4

#define ERR_FILE_INCOMPATIBLE 5018//new MQL4

#define ERR_FILE_IS_DIRECTORY 5019//new MQL4

#define ERR_FILE_NOT_EXIST 5020//new MQL4

#define ERR_FILE_CANNOT_REWRITE 5021//new MQL4

#define ERR_FILE_WRONG_DIRECTORYNAME 5022//new MQL4

#define ERR_FILE_DIRECTORY_NOT_EXIST 5023//new MQL4

#define ERR_FILE_NOT_DIRECTORY 5024//new MQL4

#define ERR_FILE_CANNOT_DELETE_DIRECTORY 5025//new MQL4

#define ERR_FILE_CANNOT_CLEAN_DIRECTORY 5026//new MQL4

#define ERR_FILE_ARRAYRESIZE_ERROR 5027//new MQL4

#define ERR_FILE_STRINGRESIZE_ERROR 5028//new MQL4

#define ERR_FILE_STRUCT_WITH_OBJECTS 5029//new MQL4