you could try this first;

open control panel, select java  plugin, then set the plugin to
\program files\java soft\ then the path to the later version of java
jre-1.4 or something similar i dont know it off hand.

windows 98 is aweful for java. ive used 2000 since it came out, but
got involved in java about 2 years ago, so i never really used java on
98. my college friends told me of the troubles they had trying to use
java 1.4 on 98. it may be just that 2000 doesnt come with java so
installing it is far easier.

my advice is to use mozilla/netscape/firebird with the java plugin.

its not a good answer  i know, but unless you can find a way to remove
java from 98 i can not help you.

java.sun.com/.../download-windows.html

i havnt read the release notes but they may contain information which
helps in a situation like this.