Security problems with 2 browsers

[J. Dobson]

I simply tried to start an on-line account with my utility co and would like
do so with some other co's, but I received the message below. My stats: Mac
OS9.2

I thought that I had the latest versions of those browsers (that can be used
with 9.2). What are my options?

IE5.1: "Security failure. Data decryption error."

Netscape 6: "To optimize your visit.... we suggest using a browser with
128-bit encryption. this will allow you to perform a wide range of online
services in a secure and pleasing online environment.
 The current versions of such browsers as Microsoft Internet Explorer and
Netscape Navigator provide this level of security. If you are having
difficulty using our online services, you may need to upgrade your browser.
  Please be aware that you are seeing this message because the browser you
are currently using is not fully supported by our site. You may experience
difficulty using our site and/or content may not be presented as originally
intended."

Jackie