连接数据库失败

我用的JSP服务器是resin，要连接sybase数据库，已经下载了Jconnet，但是连接数据库总是失败。出现如下错误信息：
500 Servlet Exception
java.lang.NullPointerException
at _conn__jsp._jspService(/conn.jsp:29)
at com.caucho.jsp.JavaPage.service(JavaPage.java:74)
at com.caucho.jsp.Page.subservice(Page.java:485)
at com.caucho.server.http.FilterChainPage.doFilter(FilterChainPage.java:179)
at com.caucho.server.http.Invocation.service(Invocation.java:288)
at com.caucho.server.http.CacheInvocation.service(CacheInvocation.java:132)
at com.caucho.server.http.ServletServer.serviceTop(ServletServer.java:937)
at com.caucho.server.http.HttpRequest.handleRequest(HttpRequest.java:213)
at com.caucho.server.http.HttpRequest.handleConnection(HttpRequest.java:158)
at com.caucho.server.TcpConnection.run(TcpConnection.java:140)
at java.lang.Thread.run(Thread.java:484)

请高手指点！多谢了！