This web site works fine under:
Apache 1.3.22 / PHP 4.0.6
Apache 1.3.24 / PHP 4.1.2

Stopped working with:
Apache 1.3.24 / PHP 4.2.0

Did something change with the way global variables or form 
variables are handled from versions < 4.2 to current?

below is what seems to be one of the offending lines of 
code. Basically, all it is doing is checking for the 
existance of 2 query strings which are passed in and used 
as global variables for several other functions within the 
site.

if ( ! $pm || ! $pc ) {
  header( "Location:     
main.php?pm=1&mm=0&sm=0&pc=homeowner/ho_mm0sm0.php");
    }