VelocityViewServlet : Error processing a template for path '/gc_default_wzcontent.html'

java.lang.IllegalArgumentException: Illegal group reference
	at java.util.regex.Matcher.appendReplacement(Matcher.java:713)
	at com.mysteel.publish.application.ArticleAOImpl.filterImages(ArticleAOImpl.java:485)
	at com.mysteel.publish.application.ArticleAOImpl.getArticleById(ArticleAOImpl.java:262)
	at com.mysteel.publish.interfaces.tag.ArticleTool.get(ArticleTool.java:23)
	at sun.reflect.GeneratedMethodAccessor60.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
	at java.lang.reflect.Method.invoke(Method.java:597)
	at org.apache.velocity.util.introspection.UberspectImpl$VelMethodImpl.invoke(UberspectImpl.java:295)
	at org.apache.velocity.runtime.parser.node.ASTMethod.execute(ASTMethod.java:245)
	at org.apache.velocity.runtime.parser.node.ASTReference.execute(ASTReference.java:203)
	at org.apache.velocity.runtime.parser.node.ASTReference.value(ASTReference.java:419)
	at org.apache.velocity.runtime.parser.node.ASTExpression.value(ASTExpression.java:73)
	at org.apache.velocity.runtime.parser.node.ASTSetDirective.render(ASTSetDirective.java:125)
	at org.apache.velocity.runtime.parser.node.SimpleNode.render(SimpleNode.java:318)
	at org.apache.velocity.Template.merge(Template.java:254)
	at org.apache.velocity.tools.view.servlet.VelocityViewServlet.performMerge(VelocityViewServlet.java:762)
	at org.apache.velocity.tools.view.servlet.VelocityViewServlet.mergeTemplate(VelocityViewServlet.java:719)
	at org.apache.velocity.tools.view.servlet.VelocityViewServlet.doRequest(VelocityViewServlet.java:551)
	at org.apache.velocity.tools.view.servlet.VelocityViewServlet.doGet(VelocityViewServlet.java:507)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:617)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:298)
	at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:852)
	at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:588)
	at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:396)
	at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
	at java.lang.Thread.run(Thread.java:619)