if you're using custom master page and sharepoint 2010, just remove the control that used '/_layouts/WebAnalytics/WebAppSelection.aspx' as StartingNodeUrl.
<%--<asp:Content ID="Content1" runat="server" ContentPlaceHolderID="PlaceHolderLeftNavBar">
<SharePoint:VersionedPlaceHolder UIVersion="4" runat="server">
<div class="ms-quicklaunchouter">
<div class="ms-quickLaunch" style="width:100%">
<SharePoint:AspMenu
id="V4QuickLaunchMenu"
DataSourceID="siteMapDataSource"
runat="server"
EnableViewState="false"
UseSimpleRendering="true"
CssClass="s4-ql"
Orientation="Vertical"
StaticDisplayLevels="3"
>
</SharePoint:AspMenu>
<asp:SiteMapDataSource ID="siteMapDataSource" runat="server" SiteMapProvider="SPXmlContentMapProvider" StartingNodeUrl ="/_layouts/WebAnalytics/WebAppSelection.aspx" ShowStartingNode="false"/>
</div>
</div>
</SharePoint:VersionedPlaceHolder>
</asp:Content>--%>
Control Location:
C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\14\TEMPLATE\LAYOUTS\WebAnalytics\Report.aspx