I think the major illegal version circulating around the internet, "Postality Knight's Edition", should actually say that that's what it is somewhere in the zip file you downloaded, etc.. If it doesn't say that, and/or if you actually downloaded it from Enterbrain's official website or a large Enterbrain game maker community like RPG RPG Revolution or similar, then you've probably got a legal copy.
I'm not really sure what else to tell you about the errors, then, other than googling something along the lines of "fix ntitles server error windows 7" and seeing if anything comes up. As I said, it worked just fine for me, so I wouldn't know how to fix it. Sorry.
EDIT: Hm... actually, I suppose it's possible a firewall or something could be blocking the program's access to the internet. See if temporarily disabling any firewalls helps. If not, then... yeah, I got nothing.