海康SDK 回调函数结束后出错

--HCNetSDK-- 单元
...type
LPNET_DVR_ALARMER = ^NET_DVR_ALARMER;
NET_DVR_ALARMER=Record
  byUserIDValid: Byte;
  bySerialValid: Byte;
  byVersionValid: Byte;
  byDeviceNameValid: Byte;
  byMacAddrValid: Byte;
  byLinkPortValid: Byte;
  byDeviceIPValid: Byte;
  bySocketIPValid: Byte;
  lUserID: LongInt;
  sSerialNumber: Array [0..SERIALNO_LEN-1] of Byte;
  dwDeviceVersion: LongInt;
  sDeviceName: Array [0..NAME_LEN - 1] of char;
  byMacAddr: Array [0..SERIALNO_LEN-1] of Byte;
  wLinkPort: Word;
  sDeviceIP: Array [0..127] of Char;
  sSocketIP: Array [0..127] of Char;
  byIpProtocol: Byte;
  byRes2: Array [0..10] of Byte;
end;type
LPNET_DVR_ALARMINFO = ^NET_DVR_ALARMINFO;
NET_DVR_ALARMINFO = record
  dwAlarmType: LongInt;
  dwAlarmInputNumber: LongInt;
  dwAlarmOutputNumber: Array [0..MAX_ALARMOUT - 1] of LongInt;
  dwAlarmRelateChannel: Array [0..MAX_CHANNUM - 1] of LongInt;
  dwChannel: Array [0..MAX_CHANNUM - 1] of LongInt;
  dwDiskNumber: Array [0..MAX_DISKNUM - 1] of LongInt;
end;...
---UHCNetSdkDll--- 单元
type
   TMessageCallback = procedure(lCommand:longint;pAlarmer:LPNET_DVR_ALARMER;pAlarmInfo:Pchar;dwBufLen:LongInt;pUser:pointer);
   procedure NET_DVR_SetDVRMessageCallBack_V30(msgCallback:TMessageCallback;lUserID:pointer);stdcall;external 'HCNetSDK.dll';---UTest---单元var
  Form1: TForm1;
  procedure MessageCallBak(lCommand:longint;pAlarmer:LPNET_DVR_ALARMER;pAlarmInfo:Pchar;dwBufLen:LongInt;pUser:pointer);
implementation{$R *.dfm}procedure MessageCallBak(lCommand:longint;pAlarmer:LPNET_DVR_ALARMER;pAlarmInfo:Pchar;dwBufLen:LongInt;pUser:pointer);
var
  I :Integer;
  //struAlarmInfo: NET_DVR_ALARMINFO;
begin
 showMessage(IntToStr(lCommand));
end;