为何我用CreateProcessW()方式运行C:\db\bin\mysqld --init-file=C:\db\my.ini会出现创建线程失败?

执行函数如下:
CString ExecuteCommandLine(CString strCmdLine)
{
SECURITY_ATTRIBUTES sa;
HANDLE hRead,hWrite; sa.nLength = sizeof(SECURITY_ATTRIBUTES);
sa.lpSecurityDescriptor = NULL;
sa.bInheritHandle = TRUE;
if (!CreatePipe(&hRead,&hWrite,&sa,0)) {
MessageBox(_T("Error On CreatePipe()"));
return _T("");
} STARTUPINFO si;
PROCESS_INFORMATION pi; si.cb = sizeof(STARTUPINFO);
GetStartupInfo(&si);
si.hStdInput=NULL; 
si.hStdError = hWrite;
si.hStdOutput = hWrite;
si.wShowWindow = SW_HIDE;
si.dwFlags = STARTF_USESHOWWINDOW|STARTF_USESTDHANDLES;
if (!CreateProcessW(NULL,strCmdLine.GetBuffer(), 
NULL,NULL,TRUE,REALTIME_PRIORITY_CLASS,NULL,NULL,&si,&pi)) {
MessageBox(_T("Error on CreateProcess()"));
return _T("");
} CloseHandle(hWrite); char buffer[4096] = {0};
CString strBuffer;
DWORD bytesRead = 0;
do{
bytesRead = 0;
memset(buffer, 0, sizeof(buffer));
ReadFile(hRead,buffer,4096,&bytesRead,NULL);
strBuffer += buffer;
}while( bytesRead == 4096);

// Wait until child processes exit.
WaitForSingleObject( pi.hProcess, 0 ); // Close process and thread handles.
CloseHandle( pi.hProcess );
CloseHandle( pi.hThread ); return strBuffer;
}