감사합니다.^^ 덕분에 해결했습니다.^^
결국 델파이 dll을 수정하는 방법밖에 없나 보네요..~~
여하튼 도움주셔서 해결이 되었네요.~
정말 감사드려요~~

김도완 님이 쓰신 글 :
: 이 글을 참고하셔요.
: http://www.devx.com/tips/Tip/37587
:
:
: 정필준 님이 쓰신 글 :
: : 아래의 dll을 만든 후 vb6에서 호출하면 vb6가 멈춥니다.
: : vb6에서 어떻게 호줄해야 하는지 고수분들의 조언을 부탁드릴게요.^^~~
: : 답변 꼭 부탁드리곘습니다. 감사합니다.~~
: : ======================================================================================================
: : vb6 코드
: : ======================================================================================================
: : Private Declare Function DllPchar Lib "C:\TEST\Project2.dll" (ByVal AStr As String) As String
: :
: : Private Sub Command10_Click()
: : Dim tmp as String
: :
: : tmp  = DllPchar("123");
: :
: : End Sub
: : ======================================================================================================
: : 델파이 코드
: : ======================================================================================================
: : library Project2;
: :
: : { Important note about DLL memory management: ShareMem must be the
: :   first unit in your library's USES clause AND your project's (select
: :   Project-View Source) USES clause if your DLL exports any procedures or
: :   functions that pass strings as parameters or function results. This
: :   applies to all strings passed to and from your DLL--even those that
: :   are nested in records and classes. ShareMem is the interface unit to
: :   the BORLNDMM.DLL shared memory manager, which must be deployed along
: :   with your DLL. To avoid using BORLNDMM.DLL, pass string information
: :   using PChar or ShortString parameters. }
: :
: : uses
: :   SysUtils,
: :   Classes,
: :   Windows;
: :
: : {$R *.res}
: :
: : function DllPchar( AStr: PChar) : PChar; stdcall;
: : var
: : S : string;
: : begin
: : S := AStr;
: : S := 'DLL 함수 테스트 : ' + S + ' - stdcall';
: : Result := PChar(S);
: : end;
: :
: : exports
: : DllPchar;
: :
: : begin
: : end.
: : ======================================================================================================
: :