Some PHP apps causing problems with mod_layout

Hi,

I've just recently installed mod_layout on our webserver, so that I 
could include some Urchin visitor tracking stuff on every page of every 
site here (this would take wayy too much time doing it by hand).  It 
works great mostly, but some pages (so far just larger PHP software 
packages) are having problems.  Instead of the page showing up with the 
line added to the header, just a few unprintable characters show up.  So 
far I've noticed this with phpMyAdmin and MediaWiki.  I'm hoping someone 
here has run into these issues and has some fix or workaround?  I 'd 
really appreciate it.  Here are the relevant lines from httpd.conf:

     # Urchin UTM stuff
     <IfModule mod_layout.c>
         LayoutMerge On
         LayoutMergeBeginTag <head*>
         LayoutMergeEndTag </head>
         LayoutFooter /www/utm.html
         CustomLog /drive2/logfiles/utm/domain.com special
     </IfModule>

/www/utm.html contains:

<script src="/__utm.js" type="text/javascript"></script>

Any help would be great.

Thanks,
Mike