Index: tracspamfilter/templates/admin_spammonitor.html
===================================================================
--- tracspamfilter/templates/admin_spammonitor.html	(revision 4652)
+++ tracspamfilter/templates/admin_spammonitor.html	(working copy)
@@ -44,7 +44,7 @@
                 <input type="checkbox" name="sel" value="${entry.id}" />
               </td>
               <td class="author" py:with="auth = entry.authenticated and 'yes' or 'no'"
-                  title="${len(entry.author) > 25 and entry.author or None}">
+                  title="${entry.author and len(entry.author) > 25 or None}">
                 <a href="$entry_href"><img src="${href.chrome('spamfilter', auth + '.gif')}"
                      title="User was ${entry.authenticated and 'was' or 'was not'} logged in"
                      alt="$auth" />&nbsp;${shorten_line(entry.author, 25) or 'anonymous'}</a>