CD-WOW use Java on their site, so it may be because you have an older version of the Java VM on your machine. Try downloading and installing the new JRE from java.sun.com. Might also be your firewall.
You should shed Netscape anyway if you're using a Windows box because it's a poor, poor browser compared to IE. And before you shout about poor web design on CD-WOW's part, just bear in mind that Netscape has only recently made its browsers more W3-standards compliant, which naturally doesn't help web designers any. Which version of Netscape are you using anyway? I had no end of problems with Java applets in Netscape 6 onwards so it was then that Netscape and I parted company.
I'm not using windows and I try and avoid it like the plague . I use unix and linux at work(at home I have windows but thats on very old PC!)
Anyway I don't want to start a windows via PC thing as this would be way off topic!
It is onl a couple of pages that the button doesn't work so I am sure its just a couple of missing links!
Probably just as well as I really don't have the money to afford the DVD (just about to buy a house )
Have you tried telling them about your problem? I had a similar issue whereby everytime I pressed the 'checkout' button the site crashed! They sent me an alternative link to purchase from which worked fine.
You can also download an order form and order by post.