So you can scan most of your PCs except for 4 of them, correct? And they are NT based (NT4/W2K/WinXP/W2K3)?
You could try testing to see if you can visit the machine through \"My Network Places\" and double-clicking one of the 4 you\'re having a problem with. Windows should ask for a password. Please let us know if you\'re able to access the machine supplying credentials with Windows, but not NEWT. We should be using the same method, so the same username/password should work.