Help:Report-Smith->using dll

Hi 'Experts!
My Problem: When I attempt to use an Delphi 1.0-dll
in Report-Smith 2.5 under win-95 the program crashes.
In Makro-Basic I used:

Declare function DoChange Lib "test.dll" (ByVal hwnd as integer) as string

Sub ChangeIntToString
        a=5
        call DoChange(a)
        b$=DoChange(a)
        DerivedField b$
End sub

In the dll :

library test ;
uses SysUtils;

function DoChange(a:integer):string;export;
        begin
                DoChange := IntToStr(a);
        end;

exports DoChange;

begin

end.

Any suggestions?
Thanks Frank.