After defining a parameter while previewing I am getting below exception, how can I address the problem.<br />
<br />
<pre class='_prettyXprint _lang-auto _linenums:0'>
<scalar-parameter name="drill_down_url" id="2">
<text-property name="displayName">Drilldown Url</text-property>
<property name="hidden">false</property>
<property name="dataType">string</property>
<property name="allowBlank">true</property>
<property name="controlType">text-box</property>
<property name="defaultValue">"http://comp11248:8080//reports/birt.do"</property>
<structure name="format">
<property name="category">Unformatted</property>
<property name="pattern">Unformatted</property>
</structure>
</scalar-parameter>
</pre>
<span class='bbc_underline'><strong class='bbc'><br />
Exception Message:</strong></span><br />
<pre class='_prettyXprint _lang-auto _linenums:0'>- java.lang.String cannot be cast to org.eclipse.birt.report.model.api.Expression
java.lang.ClassCastException: java.lang.String cannot be cast to org.eclipse.birt.report.model.api.Expression
at org.eclipse.birt.report.engine.api.impl.EngineTask.evaluateDefaultValue(EngineTask.java:1154)
at org.eclipse.birt.report.engine.api.impl.EngineTask$2.visitScalarParameter(EngineTask.java:1507)
at org.eclipse.birt.report.engine.api.impl.EngineTask$ParameterVisitor.visit(EngineTask.java:1431)
at org.eclipse.birt.report.engine.api.impl.EngineTask$ParameterVisitor.visit(EngineTask.java:1403)
at org.eclipse.birt.report.engine.api.impl.EngineTask.usingParameterValues(EngineTask.java:1534)
at org.eclipse.birt.report.engine.api.impl.GetParameterDefinitionTask.getDefaultValue(GetParameterDefinitionTask.java:339)
at org.eclipse.birt.report.service.BirtViewerReportService.getParameterDefaultValue(BirtViewerReportService.java:1004)
at org.eclipse.birt.report.context.ViewerAttributeBean.getDefaultValues(ViewerAttributeBean.java:928)
at org.eclipse.birt.report.context.ViewerAttributeBean.__initParameters(ViewerAttributeBean.java:276)
at org.eclipse.birt.report.context.ViewerAttributeBean.__init(ViewerAttributeBean.java:231)
at org.eclipse.birt.report.context.BaseAttributeBean.init(BaseAttributeBean.java:233)
at org.eclipse.birt.report.context.ViewerAttributeBean.<init>(ViewerAttributeBean.java:118)
at org.eclipse.birt.report.context.BirtContext.__init(BirtContext.java:44)
at org.eclipse.birt.report.context.BaseContext.<init>(BaseContext.java:69)
at org.eclipse.birt.report.context.BirtContext.<init>(BirtContext.java:30)
at org.eclipse.birt.report.servlet.BirtEngineServlet.__getContext(BirtEngineServlet.java:76)
at org.eclipse.birt.report.servlet.BaseReportEngineServlet.doGet(BaseReportEngineServlet.java:163)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:707)
at org.apache.axis.transport.http.AxisServletBase.service(AxisServletBase.java:327)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)
at org.eclipse.birt.report.servlet.BaseReportEngineServlet.service(BaseReportEngineServlet.java:116)
at org.eclipse.equinox.http.registry.internal.ServletManager$ServletWrapper.service(ServletManager.java:180)
at org.eclipse.equinox.http.servlet.internal.ServletRegistration.service(ServletRegistration.java:61)
at org.eclipse.equinox.http.servlet.internal.ProxyServlet.processAlias(ProxyServlet.java:126)
at org.eclipse.equinox.http.servlet.internal.ProxyServlet.service(ProxyServlet.java:60)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)
at org.eclipse.equinox.http.jetty.internal.HttpServerManager$InternalHttpServiceServlet.service(HttpServerManager.java:318)
at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:511)
at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:390)
at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182)
at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:765)
at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
at org.mortbay.jetty.Server.handle(Server.java:326)
at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542)
at org.mortbay.jetty.HttpConnection$RequestHandler.headerComplete(HttpConnection.java:924)
at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:549)
at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:212)
at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404)
at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:409)
at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:582)
</pre>
