It's not that the passwords don't match (I do not have access to anyone's password, so that's just what I assume), but the remember password browser feature is wonky in connection to the marketplace. It has never worked properly in the marketplace for me, so I guess that's where the problem lies.
I suggest you enter in manually, or if you want to sell a lot of things and it's a hassle, you write it somewhere, copy it and then just paste it manually.
I don't know why the remembered passwords don't work in the marketplace, but it has always been like this, so I doubt starkad will ever solve that problem.
