PHP 4.2.3 install under x86 RedHat 8.0 keeps SIDs in URL

Evening, all: Looking for some suggestions for troubleshooting. We're in the processing of moving a PHP application from a Solaris box to a Linux box. The Linux Box in question is a Pentium 4 running RedHat 8.0 (as shipped from Dell). We're running the IMP Webmail software, though this doesn't appear to be related to the application from troubleshooting so far. The Apache 1.3.27 w/ PHP 4.2.3 setup that we have working insists on placing the SIDs in the URL instead of using cookies. I've had similar results when I've configured 4.2.2 and 4.3.1. Moving over the current php code we're running without problem on the solaris server... the SIDs start to show up in the URL again. I'm compiling PHP with the following parameters - --with-apache=(path to apache sources) --with-mysql=/usr --with-imap=(path to c- client 2002, compiled without ssl) --with-ldap --with-gettext --disable-debug -- prefix=(path to where I install the php files). Under 4.3.1, I tried to force sessions through cookies only, and then people couldn't login (couldn't use the session). Even moving over the 4.2.2 sources that worked fine on the solaris box, making clean and compiling those, have the SID showing up in the URL. If anyone can suggest further troubleshooting ideas, or has some thoughts on possible solutions, I'm all up to hear them. Thanks for your time. mb.