Oh, I want to point out a

Oh, I want to point out a possible thing to check. MDTK may not connect because the password you type is not right, even if you think it's right. If you are using any special keyboard layouts that is not "US-English" in Windows, you risk a chance of running into this. Go back in MEBx try to change your computer name and type in your password in that box, look at what is actualy written. Because MEBx uses US-English and Windows uses a different keyboard layout, you may see the problem right away.

Ylian