Help me, Exception when export to pdf

Hi
I'm using iReport to make file jrxml, and then in my java code, I call export to pdf. But show the Error :
( I think it because of I define pdf Font in iReport)

net.sf.jasperreports.engine.JRException: Could not load the following font :
pdfFontName : arial.ttf
pdfEncoding : Identity-H
isPdfEmbedded : true

at net.sf.jasperreports.engine.export.JRPdfExporter.getChunk(JRPdfExporter.java:1429)

at net.sf.jasperreports.engine.export.JRPdfExporter.getPhrase(JRPdfExporter.java:1352)

at net.sf.jasperreports.engine.export.JRPdfExporter.exportText(JRPdfExporter.java:1658)

at net.sf.jasperreports.engine.export.JRPdfExporter.exportElements(JRPdfExporter.java:549)

at net.sf.jasperreports.engine.export.JRPdfExporter.exportPage(JRPdfExporter.java:513)

at net.sf.jasperreports.engine.export.JRPdfExporter.exportReportToStream(JRPdfExporter.java:478)

at net.sf.jasperreports.engine.export.JRPdfExporter.exportReport(JRPdfExporter.java:288)

at net.sf.jasperreports.engine.JasperExportManager.exportReportToPdfFile(JasperExportManager.java:126)

at com.fss.isp.bean.JasperReportBean.buildReport(JasperReportBean.java:113)

at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)

at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)

at java.lang.reflect.Method.invoke(Method.java:324)

at com.fss.ddtp.Processor.processRequest(Processor.java:62)

at com.fss.ddtp.ServletServer.service(ServletServer.java:65)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)

at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:237)

at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157)

at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:214)

at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)

at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)

at org.apache.catalina.core.StandardContextValve.invokeInternal(StandardContextValve.java:198)

at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:152)

at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)

at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)

at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:137)

at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)

at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:117)

at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:102)

at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)

at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)

at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)

at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)

at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:929)

at org.apache.coyote.tomcat5.CoyoteAdapter.service(CoyoteAdapter.java:160)

at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:799)

at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection(Http11Protocol.java:705)

at org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java:577)

at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:683)

at java.lang.Thread.run(Thread.java:534)



So how can java understand these Fonts? (I'm using JBuilder 2005 )
Thanks very much