为什么DLL出错？？，急呀！！（Access Violation at address 002B7F56 in module 'calbom.dll',read

为什么DLL出错？？，急呀！！（Access Violation at address 002B7F56 in module 'calbom.dll',read of address '0000005C'）(100分)<br />DLL内容:
library calbom;

uses
ShareMem,
SysUtils,
DB,
ComCtrls,
Classes,
QDialogs,
BomDataMoudle in '../BomDataMoudle.pas' {DataModule1: TDataModule};

{$R *.res}

Procedure expand(itnamechar;bomview:TTreeView);StdCall;
Begin
//程序中有调用ClientDataset
End;

Exports
expand;

begin
end.


调用DLL的程序如下:
unit BOMAdd;

interface

uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls, Buttons, ComCtrls, ExtCtrls, DBCtrls, Mask, Grids,
DBGrids,DB;

type
TBom_Add = class(TForm)
GroupBox1: TGroupBox;
Label1: TLabel;
TItem: TEdit;
SBS1: TSpeedButton;
SBR1: TSpeedButton;
Label2: TLabel;
TDp: TEdit;
BOMTree: TTreeView;
procedure SBS1Click(Sender: TObject);
procedure BOMTreeClick(Sender: TObject);
procedure BOMTreeDblClick(Sender: TObject);
procedure SBR1Click(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;

var
Bom_Add: TBom_Add;

implementation

uses BomDataMoudle;
Procedure expand(itnamechar;bomview:TTreeView);StdCall
external 'calbom.dll';

{$R *.dfm}

procedure TBom_Add.SBS1Click(Sender: TObject);
var
Str:String;
testchar;
Begin
With BOMDM.C310 Do
Begin
close;
str:='Select item,part,unit,levels,begins,ends,Scrap From s310 Order by item,part';
commandtext:=str;
open;
End;

With BOMDM.C310S Do
Begin
close;
str:='Select part,keys,um,dp,line from s130 Order by part';
commandtext:=str;
open;
End;
test:=pchar(trim(TItem.text));
expand(test,BOMTree);
end;

itname没有分配内存

楼上兄台，要怎么分配内存啊

兄弟姐妹们，找个办法给我呀，谢啦