[Zope] DTML Question

[Michael]

I use the following snippet of code in one way and it works fine.  I try 
to use another way and nothing happens, I just get a blank screen. The 
paths is correct.

   <dtml-with "sites.specifics">
     <dtml-if "target_url() == 'my_url'">
       <dtml-var site_url>
       <dtml-var site_logo>
       <dtml-var site_name>
       <dtml-var site_acronym>
     </dtml-if>
   </dtml-with>

This seems to work fine and it will pull up all the objects in the 
folder.  But when I try to get this to work with my Contacts Product or 
Folder, nothing happens.  I've tried to access my Catalog:

   <dtml-with "Contacts.Catalog">
     <dtml-if "contact_tracking() == '100467893'">
       <dtml-var contact_fname>
       <dtml-var contact_lname>
       <dtml-var contact_street>
       <dtml-var contact_city>
     </dtml-if>
   </dtml-with>

But nothing happens.  I tried to access my entries folder also:

   <dtml-with "Contacts.entries">
     <dtml-if "contact_tracking() == '100467893'">
       <dtml-var contact_fname>
       <dtml-var contact_lname>
       <dtml-var contact_street>
       <dtml-var contact_city>
     </dtml-if>
   </dtml-with>

Can somebody give me a hint as to what I'm doing wrong here, besides 
staying up all night:-(

Thanks,

Michael