Unlikely to be true for a program nearly 4 years old. You can try the same program from another downloadsite http://www.softpedia.com/get/Internet/Browsers/Netscape-Browser.shtml , but that should be the same.
So my guess is a false positive. Upload it to www.virustotal.com and see what other programs say.
i downloaded netscape navigator from cnet.com 5 minutes ago and my super antispyware pro detected trojan agent/gen-ban load process. it is the netscape navigator 22.214.171.124.EXE