The size required by the instruction operand does not match the size given.

program Produce;

  var
    v : Integer;

  procedure Assembly;
  asm
    db offset v
  end;

begin
end.

In the sample above, the compiler will complain because the 'offset' operator produces a 'dword', but the operator is expecting a 'byte'.

program Solve;

  var
    v : Integer;

  procedure Assembly;
  asm
    dd offset v
  end;

begin
end.

The solution, for this example, is to change the operator to receive a 'dword'. In the general case, you will need to closely examine your code and ensure that the operator and operand sizes match.