急!急!急!用java打开已发布好的报表出现问题

当我使用java文件去打开已发布好的报表时

IReportAppFactory rptAppFactory = (IReportAppFactory)
ceSession.getService("RASReportService");
ReportClientDocument clientDoc = rptAppFactory.openDocument(report, 0, Locale.CHINESE);

报这样的错误:
com.crystaldecisions.sdk.occa.managedreports.ras.internal.a: 无法打开报表文档。 --- 无法与服务器 RPTSERVER.RAS.rptappserver 连接。 --- Stopping after fatal error: An invalid XML character (Unicode: 0xffff) was found in the element content of the document.
cause:com.crystaldecisions.sdk.occa.report.lib.ReportSDKServerException: 无法与服务器 RPTSERVER.RAS.rptappserver 连接。 --- Stopping after fatal error: An invalid XML character (Unicode: 0xffff) was found in the element content of the document.---- Error code:-2147467259 Error code name:failed
detail:无法打开报表文档。 --- 无法与服务器 RPTSERVER.RAS.rptappserver 连接。 --- Stopping after fatal error: An invalid XML character (Unicode: 0xffff) was found in the element content of the document.
The exception originally thrown was com.crystaldecisions.sdk.occa.report.lib.ReportSDKServerException: 无法与服务器 RPTSERVER.RAS.rptappserver 连接。 --- Stopping after fatal error: An invalid XML character (Unicode: 0xffff) was found in the element content of the document.---- Error code:-2147467259 Error code name:failed
at com.crystaldecisions.sdk.occa.managedreports.ras.internal.RASReportAppFactory.a(Unknown Source)
at com.crystaldecisions.sdk.occa.managedreports.ras.internal.RASReportAppFactory.a(Unknown Source)
at com.crystaldecisions.sdk.occa.managedreports.ras.internal.RASReportAppFactory.openDocument(Unknown Source)

望各位大虾们帮忙看看 这是为什么呀?