Apache2 conundrum - update

[Neil Joseph Schelly]

I think it would help if you found out what index.php code is running when you 
make the http://sitename/ request.  Try adding something to that doesn't 
exist (http://sitename/doesntexist/, so that Apache's error log will show you 
a path to the file it can't find.

Is it possible that there's a MultiViews configuration in place here that may 
be directing requests to a less obvious file?  Did the upgrades you had 
change the Apache configuration with regard to DirectoryIndex options?  Did 
those upgrades change the lines in the Apache configuration that 
load/configure mod_php?  
-N