500 Servlet Exception

java.lang.StringIndexOutOfBoundsException: String index out of range: -4
	at java.lang.String.substring(String.java:1444)
	at java.lang.String.substring(String.java:1411)
	at _q_0a._index__jsp._jspService(/opt/webapps/q_a/index.jsp:977)
	at com.caucho.jsp.JavaPage.service(JavaPage.java:75)
	at com.caucho.jsp.Page.subservice(Page.java:506)
	at com.caucho.server.http.FilterChainPage.doFilter(FilterChainPage.java:182)
	at com.caucho.server.http.Invocation.service(Invocation.java:315)
	at com.caucho.server.http.CacheInvocation.service(CacheInvocation.java:135)
	at com.caucho.server.http.RunnerRequest.handleRequest(RunnerRequest.java:346)
	at com.caucho.server.http.RunnerRequest.handleConnection(RunnerRequest.java:274)
	at com.caucho.server.TcpConnection.run(TcpConnection.java:139)
	at java.lang.Thread.run(Thread.java:534)