popularissues-panel.vm: $constant.getString("iconurl") is not a valid reference

2005-01-18 02:22:41,470 ERROR [velocity] Left side ($constant.getString("iconurl").startsWith("http://")) of '==' operation has null value. If a reference, it may not be in the context. Operation not possible. templates/plugins/jira/projectpanels/popularissues-panel.vm [line 1, column 61]
2005-01-18 02:22:41,473 WARN [velocity] org.apache.velocity.runtime.exception.ReferenceException: reference : template = templates/plugins/jira/projectpanels/popularissues-panel.vm [line 4,column 27] : $constant.getString("iconurl") is not a valid reference.
at org.apache.velocity.runtime.parser.node.ASTReference.render(ASTReference.java:277)
at org.apache.velocity.runtime.parser.node.ASTBlock.render(ASTBlock.java:55)
at org.apache.velocity.runtime.parser.node.SimpleNode.render(SimpleNode.java:230)
at org.apache.velocity.runtime.parser.node.ASTIfStatement.render(ASTIfStatement.java:89)
at org.apache.velocity.runtime.parser.node.SimpleNode.render(SimpleNode.java:230)
at org.apache.velocity.runtime.directive.VelocimacroProxy.render(VelocimacroProxy.java:172)
at org.apache.velocity.runtime.parser.node.ASTDirective.render(ASTDirective.java:114)
at org.apache.velocity.runtime.parser.node.ASTBlock.render(ASTBlock.java:55)
at org.apache.velocity.runtime.directive.Foreach.render(Foreach.java:166)
at org.apache.velocity.runtime.parser.node.ASTDirective.render(ASTDirective.java:114)
at org.apache.velocity.runtime.parser.node.ASTBlock.render(ASTBlock.java:55)
at org.apache.velocity.runtime.parser.node.ASTIfStatement.render(ASTIfStatement.java:70)
at org.apache.velocity.runtime.parser.node.SimpleNode.render(SimpleNode.java:230)
at org.apache.velocity.Template.merge(Template.java:256)
at org.apache.velocity.app.VelocityEngine.mergeTemplate(VelocityEngine.java:450)
at com.atlassian.velocity.DefaultVelocityManager.getEncodedBody(DefaultVelocityManager.java:97)
at com.atlassian.velocity.DefaultVelocityManager.getEncodedBody(DefaultVelocityManager.java:77)
at com.atlassian.jira.plugin.JiraResourcedModuleDescriptor.getHtml(JiraResourcedModuleDescriptor.java:79)
at com.atlassian.jira.plugin.projectpanel.impl.PopularIssuesProjectTabPanel.getHtml(PopularIssuesProjectTabPanel.java:52)
at com.atlassian.jira.web.action.browser.Browser.getProjectTabHtml(Browser.java:292)