Delphi – Returning a string from a BPL function

have a function, simplified below, that is exported from a BPL

function DoA(amount: currency; var Info: string): Currency; stdcall;
 begin
  result := amount * 19;
  Info:= 'Some Text about the result';
 end;

its loaded from the main program with LoadPackage, and GetProcAddress which works fine for the other functions.
but this one brings up many errors when its called;

BPL Is used with (simplified)

  bplhandle: HModule;
  BPLDoA: function (amount: currency; var Info: string): Currency; stdcall;
  intoStr : string;

.

 begin
  bplhandle:=LoadPackage('test.bpl');
   if bplhandle <> 0 then
    begin
     @BPLDoA:=GetProcAddress(bplhandle,'DoA');
       if assigned(BPLDoA) then
       result := BPLDoA(123, intoStr);
    end;
 end;

the exception that seems to happen at the end of the Procedure,
but the corrected text is returned into intoStr (viewed with a break point)

would the error have anything to do with the Info param being a var and/or a string?

The Error message is

Project Project1.exe raised exception class EInvalidPointer with message 'Invalid pointer operation'

thanks

more info>
another function from the same bpl/unit works fine

function DoB(amount: currency): Currency; stdcall;
  result := amount * 19;
 end;

Mad Except>

exception class : EInvalidPointer
exception message : Invalid pointer operation.

main thread ($1b7c):
0040276f +013 Project1.exe System @FreeMem
00404650 +01c Project1.exe System @LStrClr
00483814 +15c Project1.exe Unit1 97 +11 TForm1.Button3Click
00462430 +064 Project1.exe Controls TControl.Click
0045a870 +01c Project1.exe StdCtrls TButton.Click