调用dll出现'Invalid Pointer operation'，怎么回事？(100分)

如果调用程序和dll都带包编译，出现此错误

如何只有一方或者都不带包编译，没有此错误

而实际需求需要带包编译？

源码如下：
dll：
library wz_lld;

uses
ShareMem,
windows,
SysUtils,
forms,
Db,
DBTables,
unt_wz_lld in 'unt_wz_lld.pas' {Frm_wz_lld},
unt_wz_lld_pnt in 'unt_wz_lld_pnt.pas' {Frm_wz_lld_pnt},
unt_function in '../unt_function.pas';

function ShowChild(App:TApplication;
DbUser:ShortString;DbPassword:ShortString;BdeAls:ShortString;
ASsdw:ShortString;AUserId:ShortString;Abhdwdm,Abh:shortstring
AScrollBox:TScrollBox):integer;stdcall;
begin
ssdw := ASsdw;
userid := AUserId;
lldh := Abh;
llddwdm:=Abhdwdm;
Application:=App;
Application.Handle := app.Handle;
if not assigned(frm_wz_lld) then
frm_wz_lld := TFrm_wz_lld.Create(Application);
with Frm_wz_lld do
begin
{ BorderStyle := bsNone;
BorderIcons := [];
// align := alClient;
// WindowState:=wsMaximized;
Windows.SetParent(Handle, AScrollBox.Handle);
windows.MoveWindow(Handle, 0, 0, AScrollBox.Width,AScrollBox.Height, True)
}
show;
end;
Result:= Frm_wz_lld.Handle;
// Result:=(TFrm_wz_lld.Create(Application)).handle;
end;
{Function: Set Dll-Application Var back to originall Value}

procedure SetOldApplication;stdcall;
begin
Application:=OldApp;
end;

{$R *.RES}
exports ShowChild,SetOldApplication;
begin
{Save original Applicatioin Variable}
OldApp:=Application;
end.

调用程序：（部分）
TF_ShowChild = function (App:TApplication;
DbUser:ShortString;DbPassword:ShortString;BdeAls:ShortString;
ASsdw:ShortString;AUserId:ShortString;Abhdwdm,Abh:shortstring
AScrollBox:TScrollBox):integer;stdcall;

function TFrm_wz_lldcl.getDisposalDLLName: string;
begin
result := 'wz_lld.dll';
end;

procedure TFrm_wz_lldcl.LoadDLL(DLLName: string);
var
LastErrorWord;
begin
if dllModHandle_= 0 then
begin
dllModHandle_:=loadLibrary(pchar(DLLName));
if dllModHandle_ =0 then
begin
LastError := GetLastError;
Raise EDLLLoadError.create(IntToStr(LastError) + ': DLL不存在');
end;
ShowChild:=getProcAddress(dllModHandle_,'ShowChild');
if @showChild=Nil then begin
Raise EDLLLoadError.create(IntToStr(LastError) + ': 不能够找到函数 ShowChild');
end;
SetOldApplication:=getProcAddress(dllModHandle_,'SetOldApplication');
if @SetOldApplication=Nil then begin
Raise EDLLLoadError.create(IntToStr(LastError) + ': 不能够找到函数 SetOldApplication');
end;
end;
end;

procedure TFrm_wz_lldcl.sptnDisposalClick(Sender: TObject);
var
DLLName:string;
i:integer;
begin
if stgGrid.Cells[1,stgGrid.Row] = '' then exit;
ScrollBox1.BringToFront;
ScrollBox1.Align := alClient;
Pnl_main.SendToBack;
DLLName := getDisposalDLLName;
LoadDLL(DLLName);
i:=ShowChild(Application,'','','dBAlias_ND',
ssdw,Userid,stgGrid.cells[1,stgGrid.Row],stgGrid.cells[2,stgGrid.Row],ScrollBox1);
end;

procedure TFrm_wz_lldcl.FormDestroy(Sender: TObject);
begin
arrField := nil;

if dllModHandle_<>0 then
begin
SetOldApplication;
FreeLiBrary(dllModHandle_);
end;
end;

procedure TFrm_wz_lldcl.FormDestroy(Sender: TObject);
begin
arrField := nil;

if dllModHandle_<>0 then
begin
SetOldApplication;
FreeLiBrary(dllModHandle_);
end;
end;
这段代码加个showmessage('aa');调试
一般这个错误是内存或者指针没有释放好

这段代码没有问题，都通过的
1,如果我在dll和调用程序中都加了sharemem的话则可以调用dll，但是在调用程序退出时出错
invalid pointer operator
runtime 217 error

2,如果我在调用程序中不加sharemem的话，在调用dll时就出错
invalid pointer operator

这个问题提了这么久了，怎么没有人回答呢