updated to php 4.3.11 and squirrelmail 1.4.4 ... DB.php was no longer installed, but is needed to run squirrelmail. without it, users cannot log in. http://example.com/squirrelmail/src/configtest.php also shows that DB.php is needed. squirrelmail should RDEPEND on dev-php/PEAR-DB fyi this is not the same problem as bug #86685 or bug #88763.
might want to make this a conditional dependency based on a USE flag such as 'mysql' since not all installations have their squirrelmail configured to use databases.
fixed in cvs. thanks.