Not sure if this is entirely relevant, Naruto, but some parts of it may help. It's to do with ISDN, by the look of things.
http://www.eicon.com/support/helpweb/con2ken/isdn_wmp_install.asp
Just a thought, have you looked in Device Manager, under Modems? If you can find this 'wan miniport' in there, and uninstall it, when you restart Windows, it may well find the drivers for you.
Also, if you do a Google search for 'Wan Miniport', loads of stuff comes up, some of which may be useful to you.