[NumLock]

Код:

function BusyCallBack(p:Pointer;pr:PTUUProgress):integer;
var test:string;
begin
  Result:=0;
  test:=Pchar(p);
    Log(test);
if pr^.action=0 then ...
end;

ну и наверное:

function BusyCallBack(p:Pointer;pr:PTUUProgress):integer; stdcall;