rem: if (link) { link = link.QueryInterface(Components.interfaces.nsIRDFLiteral); 
add: if (link instanceof Components.interfaces.nsIRDFLiteral && link.Value) 
context: function onselect_loadURI(tree) {    try {        var resource = tree.view.getResourceAtIndex(tree.currentIndex);	var link = tree.database.GetTarget(resource, NC_LINK, true);	if (link) {            link = link.QueryInterface(Components.interfaces.nsIRDFLiteral);            loadURI(link.Value);        }    } catch (e) {    }// when switching between tabs a spurious row number is returned.}
meta: 10234	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/10234/685b0bb4cb5c3fb9add747b8c4f05bb40b317a51/help.js/buggy/toolkit/components/help/content/help.js