hi..
I'm using Websphere Application Server 4.0
I'm also getting the same error. If you have a solution to this problem, 
please let me know.

deepika

> I have just constructed my first custom tag usin (jakarta-tomcat-3.2.3 
using jdk1.3.1_01 on a 
> windows platform). I have done all the things the very useful 
Professional JSP 2nd Editon has 
> shown me, but and it's a big frustrating but, when I come to implement 
my custom tag in a JSP 
> all I keep getting is the following error:
> 
> Error: 500
> 
> Location: /exper/genericDBtester.jsp
> 
> Internal Servlet Error:
> 
> org.apache.jasper.compiler.CompileException: 
> C:\jakarta-tomcat-3.2.3\webapps\exper\genericDBtester.jsp(9,0) Unable to 
load class null
>         at org.apache.jasper.compiler.TagBeginGenerator.init
(TagBeginGenerator.java:129)
>         at 
> org.apache.jasper.compiler.JspParseEventListener$GeneratorWrapper.init
(JspParseEventListe
> ner.java:759)
>         at 
> org.apache.jasper.compiler.JspParseEventListener.addGenerator
(JspParseEventListener.java:
> 138)
>         at 
> org.apache.jasper.compiler.JspParseEventListener.handleTagBegin
(JspParseEventListener.jav
> a:909)
>         at 
> org.apache.jasper.compiler.DelegatingListener.handleTagBegin
(DelegatingListener.java:194)
>         at org.apache.jasper.compiler.Parser$Tag.accept(Parser.java:813)
>         at org.apache.jasper.compiler.Parser.parse(Parser.java:1077)
>         at org.apache.jasper.compiler.Parser.parse(Parser.java:1042)
>         at org.apache.jasper.compiler.Parser.parse(Parser.java:1038)
>         at org.apache.jasper.compiler.Compiler.compile(Compiler.java:209)
>         at org.apache.jasper.servlet.JspServlet.doLoadJSP
(JspServlet.java:612)
>         at org.apache.jasper.servlet.JasperLoader12.loadJSP
(JasperLoader12.java:146)
>         at org.apache.jasper.servlet.JspServlet.loadJSP
(JspServlet.java:542)
>         at 
> org.apache.jasper.servlet.JspServlet$JspServletWrapper.loadIfNecessary
(JspServlet.java:258)
>         at org.apache.jasper.servlet.JspServlet$JspServletWrapper.service
(JspServlet.java:268)
>         at org.apache.jasper.servlet.JspServlet.serviceJspFile
(JspServlet.java:429)
>         at org.apache.jasper.servlet.JspServlet.service
(JspServlet.java:500)
>         at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
>         at org.apache.tomcat.core.ServletWrapper.doService
(ServletWrapper.java:405)
>         at org.apache.tomcat.core.Handler.service(Handler.java:287)
>         at org.apache.tomcat.core.ServletWrapper.service
(ServletWrapper.java:372)
>         at org.apache.tomcat.core.ContextManager.internalService
(ContextManager.java:812)
>         at org.apache.tomcat.core.ContextManager.service
(ContextManager.java:758)
>         at 
> org.apache.tomcat.service.http.HttpConnectionHandler.processConnection
(HttpConnectionHan
> dler.java:213)
>         at org.apache.tomcat.service.TcpWorkerThread.runIt
(PoolTcpEndpoint.java:416)
>         at org.apache.tomcat.util.ThreadPool$ControlRunnable.run
(ThreadPool.java:501)
>         at  java.lang.Thread.run(Thread.java:484)
> 
> So please I am calling on all your technical know how to try and come to 
a solution to this 
> problem.
> Yours gratefully frustrated in London
> 
> 
> 
> 
> 
> 
>