Serious Problems (Apache/PHP/Sessions)

Ive been trying to get IMP 3.0 RC3 (web-based IMAP client) to work under php / apache / imap2000 c-client. When I install php 4.0.6 or 4.1.0 with apache 1.3.20 or 1.3.22 using dso/apxs everything works except for one major problem: After one is logged in (a session is opened) for a while (and other users open sessions), when you click on a page that relies on sessions the page never loads, it just stalls continuosly before timing out to "cannot display page" after about 3 - 4 minutes. If you close your session (close your browser) or clear the /tmp/sessions folder on the server, everything is fine the links work again temporarily. I might think this is something to do with IMP, but Ive tried other IMAP webmail clients, and Ive had the same problem. Ive tried 5 different platform/browser combinations. I have this problem with 4.0.6/4.1.0 and apache 1.3.20+ So next I tried compiling php into apache with -activate-module=php.. and when I do this, Apache segfaults 11 when an imap connection is opened! Ahhh! Does anyone have IMP or any other imap software running under a current version of php apache with a moderate load? Thanks, Lee