My program works fine at school and everything runs properly, but whenever I try and run it at home on my laptop i get an error message. Would anyone be able to help me?
This is the error message i get:

type Exception report

message

description The server encountered an internal error () that prevented it from fulfilling this request.

exception

javax.servlet.ServletException: Error allocating a servlet instance
    org.apache.catalina.valves.ErrorReportValve.invoke (ErrorReportValve.java:118)
    org.apache.coyote.tomcat5.CoyoteAdapter.service(Co yoteAdapter.java:160)
    org.apache.coyote.http11.Http11Processor.process(H ttp11Processor.java:799)
    org.apache.coyote.http11.Http11Protocol$Http11Conn ectionHandler.processConnection(Http11Protocol.jav a:705)
    org.apache.tomcat.util.net.TcpWorkerThread.runIt(P oolTcpEndpoint.java:577)
    org.apache.tomcat.util.threads.ThreadPool$ControlR unnable.run(ThreadPool.java:683)
    java.lang.Thread.run(Unknown Source)


root cause

java.lang.NoClassDefFoundError: Illegal name: a3classes/BooksServlet
    java.lang.ClassLoader.defineClass(Unknown Source)
    java.security.SecureClassLoader.defineClass(Unknow n Source)
    org.apache.catalina.loader.WebappClassLoader.findC lassInternal(WebappClassLoader.java:1634)
    org.apache.catalina.loader.WebappClassLoader.findC lass(WebappClassLoader.java:860)
    org.apache.catalina.loader.WebappClassLoader.loadC lass(WebappClassLoader.java:1307)
    org.apache.catalina.loader.WebappClassLoader.loadC lass(WebappClassLoader.java:1189)
    org.apache.catalina.valves.ErrorReportValve.invoke (ErrorReportValve.java:118)
    org.apache.coyote.tomcat5.CoyoteAdapter.service(Co yoteAdapter.java:160)
    org.apache.coyote.http11.Http11Processor.process(H ttp11Processor.java:799)
    org.apache.coyote.http11.Http11Protocol$Http11Conn ectionHandler.processConnection(Http11Protocol.jav a:705)
    org.apache.tomcat.util.net.TcpWorkerThread.runIt(P oolTcpEndpoint.java:577)
    org.apache.tomcat.util.threads.ThreadPool$ControlR unnable.run(ThreadPool.java:683)
    java.lang.Thread.run(Unknown Source)


note The full stack trace of the root cause is available in the Apache Tomcat/5.0.28 logs.

Everything in my system is the same as the one at school. Except at school I use Tomcat 4.

It may be your servlet mapping, the default is /servlet/yourPage (I think), i see you are using a different folder for this servlet. There is another thread in here somewhere that goes into servlet mapping, alternatively look at the tomcat documentation.