Postfix issues, unable to send email from IMP

[FreeBSD]

Current setup:

* FreeBSD 4.4RC system tracking -stable
* postfix-20010808_3 built from ports
* cyrus-imapd-2.016_1 built from ports
* Apache1.3.20+mod_ssl2.8.4 running as user 'www'
* mod_php4.0.6_4 with latest cvs'd pear dir
* recently cvs'd horde (HEAD) and IMP (HEAD)

I can see my email in IMP fine, log in fine, and save preferences through
postgresql. But when I try to send an email through compose, it just
grinds on "sending..." forever. A ps awux shows this running:

www   90441  0.0  0.1   680  312  ?? S  6:26PM  0:00.01  sh -c
/usr/local/sbin/sendmail -ftest@xtremedev.com -- test@localhost
www   90442  0.0  0.3  2592 1392  ?? S  6:26PM  0:00.05
/usr/local/sbin/sendmail -ftest@xtremedev.com -- test@localhost


Error logs show several lines like this:

postdrop: warning: mail_queue_enter: create file maildrop/599980.87606:
Permission denied


The test user exists and I can send email out from it using pine and read
mail in pine as well. Have I missed something in postfix setup to allow
'www' user to send email through Apache? Or is this a PHP/PEAR issue?