How do I view Web content that gives me the Java error "Bad version number in .class

[jayschif78]

file"? Java seems to work well on most Web sites, but a couple sites that use it aren't working for me now all of a sudden. These sites have worked fine for the past year or so until now.

I am running Windows 98 (Yes, really!) and Java Version 1.5.0 (build 1.5.0_15-b04). For some reason, I can only access certain Java-rich sites in Firefox (version 2.0.0.17) and not Internet Explorer (version 6.0.2800.1106).

Here's the full error message: "General Exception: UnsupportedClassVersionError: Bad version number in .class file"

Is this because I need to upgrade to the latest version of Java? Could the Web site be using a newer (or older) version of Java?

Please be specific in your answer, because I am no expert at programming, writing Javascript, etc.