Logged In: YES 
user_id=6405

If you view the source of the page containing that 
link, you'll notice that the attribute value is correctly 
quoted. 
 
It looks like your browser is correctly quoting the 
spaces in the URL for its request, but not escaping 
existing %. I'm not sure there's a work-around for 
this, except renaming the file in the database. 
 
To make that easier, add this extra column to your 
file listing (sorry, will wrap badly): 
 
  <td><a tal:condition="file/is_edit_ok" 
          tal:attributes="href 
string:file${file/id}">edit</a></td> 
 
Which browser, BTW?