Postmaster not stopping

Greetings:

I'm having problems stopping the postmaster.  As I'm very well aware,
kill -i on the postmaster is a Bad Thing (tm), so what are my options?
What can I look for to help me narrow down the problem?

Any help appreciated.  Below is a log from what I'm doing.

Thanks!
Chris

[root@gumby bin]# ./pg_ctl -D /var/lib/pgsql/data/ stop
waiting for postmaster to shut
down................................................................
failed
pg_ctl: postmaster does not shut down
You have mail in /var/spool/mail/cmulcahy
[root@gumby bin]# ./pg_ctl -D /var/lib/pgsql/data/ stop
waiting for postmaster to shut
down................................................................
failed
pg_ctl: postmaster does not shut down