Sure.
I used Windows XP Pro when I downloaded it on my first computer from hangame's site. Now I use Windows XP Familly Edition and I downloaded it from
http://www.arad.jp and I reinstalled it when I put japanese for non-unicode.
My computer is 2.80GHz with 3Go of RAM, my card is an ATI Radeon 4800 Series 512 MB. Drivers are updated.
Also, it's someone I met on the net that tried to bring me in this game, he's in canada and experiences the same problem as me. I don't know what are the specs of his computer or if he uses a proxy ...
I hope that helps you helping me, thanks for answering that fast !