methinks you have spyware/adware on your pc....
If you have a browser installed, it should take you to the site where you want to visit without any additional netscape browser. I suggest you do not partake of the invitation unless your sure of the source of the email and that it's valid. There are sites offering free spyware removal programs.
[url]http://www.lavasoftusa.com/software/adaware/[/url] (adaware removal program)