Index: dav/src/java/org/sakaiproject/dav/DavServlet.java
===================================================================
--- dav/src/java/org/sakaiproject/dav/DavServlet.java	(revision 5349)
+++ dav/src/java/org/sakaiproject/dav/DavServlet.java	(revision 5350)
@@ -1660,7 +1660,7 @@
 	 *        The http servlet response object.
 	 * @return any error message, or null if all went well.
 	 */
-	private String doContent(String id, HttpServletRequest req, HttpServletResponse res)
+	private String doContent(String id, HttpServletRequest req, HttpServletResponse res) throws IOException
 	{
 	        if (prohibited(id))
 			return "You do not have permission to view this resource";
@@ -1678,6 +1678,9 @@
 		}
 		catch (IdUnusedException e)
 		{
+			//Send proper header so that dav requests being improperly proxied through
+			//mod_proxy_ajp will make sense to most dav clients
+			res.sendError(HttpServletResponse.SC_NOT_FOUND, id);
 			return "This resource does not exist";
 		}
 		catch (EntityPropertyNotDefinedException e)