Cannot download attachements from Work Item Web Access
Solution provided by Hakan Eskici from Microsoft:
If you are using the WIWA feature in the latest TSWA 2008 SP1, you may notice that it’s not possible to download attachment files from the work item window.
As a workaround, you can edit Wiwa\UI\Pages\WorkItems\DownloadAttachment.aspx and modify the page directive to fix this by adding the HasPermission attribute:
<%@ Page Language="C#"
AutoEventWireup="true"
MasterPageFile="~/UI/Masters/Window.master"
Inherits="Microsoft.TeamFoundation.WebAccess.UI.Pages.WorkItems.DownloadAttachment"
Codebehind="DownloadAttachment.aspx.cs"
HasPermission="true" %>
Source: http://blogs.msdn.com/hakane/archive/2009/02/13/fix-wiwa-cannot-download-attachments.aspx