I've got two sites - development and production - both residing on the same server, both running php 4.4.4
My session variables are coming up null on the dev site, but work properly on the prod site.
The scripts are the same on both sites, except that I added echo statements to the scripts on the dev site to determine that the session variabels were null.
the last time something like this happened was in Jan/Feb and it may or may not have been related to DH upgrading to php 4.4.2.
Or, it may have had something to do with not using cookies:
At herod's suggestion, I changed the line from
ini_set ('session.use_cookies', 0);
ini_set ('session.use_cookies', 1);
from my login script, and sessions started working again.
However, since both sites are running 4.4.4, and both are running the same login script, there's got to be something else going on.
(edited to reflect the proper ini_set line)