服务器上有：database、logfiles、logs、root、workdir等5个目录，我的程序有：css、data、img、web-inf等4个目录和一些jsp文件，请问我应该把这些文件怎么放，才能正常浏览？

报错信息如下：

HTTP Status 500 -

--------------------------------------------------------------------------------

type Exception report

message

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

exception

org.apache.jasper.JasperException: /index.jsp(2,0) The value for the useBean class attribute com.guestbook.DBConnection is invalid.
    org.apache.jasper.compiler.DefaultErrorHandler.jspError(DefaultErrorHandler.java:39)
    org.apache.jasper.compiler.ErrorDispatcher.dispatch(ErrorDispatcher.java:409)
    org.apache.jasper.compiler.ErrorDispatcher.jspError(ErrorDispatcher.java:150)
    org.apache.jasper.compiler.Generator$GenerateVisitor.visit(Generator.java:1227)
    org.apache.jasper.compiler.Node$UseBean.accept(Node.java:1116)
    org.apache.jasper.compiler.Node$Nodes.visit(Node.java:2163)
    org.apache.jasper.compiler.Node$Visitor.visitBody(Node.java:2213)
    org.apache.jasper.compiler.Node$Visitor.visit(Node.java:2219)
    org.apache.jasper.compiler.Node$Root.accept(Node.java:456)
    org.apache.jasper.compiler.Node$Nodes.visit(Node.java:2163)
    org.apache.jasper.compiler.Generator.generate(Generator.java:3272)
    org.apache.jasper.compiler.Compiler.generateJava(Compiler.java:244)
    org.apache.jasper.compiler.Compiler.compile(Compiler.java:470)
    org.apache.jasper.compiler.Compiler.compile(Compiler.java:451)
    org.apache.jasper.compiler.Compiler.compile(Compiler.java:439)
    org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:511)
    org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:295)
    org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:292)
    org.apache.jasper.servlet.JspServlet.service(JspServlet.java:236)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:802)


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


--------------------------------------------------------------------------------

Apache Tomcat/5.0.28

这是什么原因引起的？怎么解决？