500 Servlet Exception

java.lang.NumberFormatException: For input string: ""
	at java.lang.NumberFormatException.forInputString(NumberFormatException.java:48)
	at java.lang.Integer.parseInt(Integer.java:447)
	at java.lang.Integer.parseInt(Integer.java:497)
	at _jsp._index__jsp._jspService(bottom.jsp:16)
	at com.caucho.jsp.JavaPage.service(JavaPage.java:61)
	at com.caucho.jsp.Page.pageservice(Page.java:578)
	at com.caucho.server.dispatch.PageFilterChain.doFilter(PageFilterChain.java:192)
	at com.caucho.server.webapp.WebAppFilterChain.doFilter(WebAppFilterChain.java:175)
	at com.caucho.server.dispatch.ServletInvocation.service(ServletInvocation.java:240)
	at com.caucho.server.hmux.HmuxRequest.handleRequest(HmuxRequest.java:424)
	at com.caucho.server.port.TcpConnection.run(TcpConnection.java:481)
	at com.caucho.util.ThreadPool$Item.runTasks(ThreadPool.java:685)
	at com.caucho.util.ThreadPool$Item.run(ThreadPool.java:607)
	at java.lang.Thread.run(Thread.java:619)