pid file problem

Hi,

On system startup PostgreSQL 8.1.4 refuses to start due to the pid
file is left over from previous "session" on Solaris 10 x86. After
removing the old pid file, PG start up and creates a new pid file:

[root@sungift] /# ls -l /var/opt/postgresql/data/postmaster.pid
-rw-------   1 postgres dba           50 Feb 12 19:47
/var/opt/postgresql/data/postmaster.pid

In the logfile I find:

LOCATION:  SocketBackend, postgres.c:295
LOG:  00000: received smart shutdown request
LOCATION:  pmdie, postmaster.c:1885
LOG:  00000: shutting down
LOCATION:  ShutdownXLOG, xlog.c:5031
FATAL:  58P01: could not remove old lock file "postmaster.pid": No
such file or directory
HINT:  The file seems accidentally left over, but it could not be
removed. Please remove the file by hand and try again.

The start and stop entries for SVC look like the following:

<exec_method
                type='method'
                name='start'
                exec='/opt/postgresql/8.1.4/bin/pg_ctl start -l
/var/opt/postgresql/log/logfile'
                timeout_seconds='60'>
                <method_context>
                    <method_credential user='postgres' group='dba' />
                    <method_environment>
                        <envvar name="TMPDIR" value="/tmp"/>
                        <envvar name="PATH"
value="/opt/postgresql/8.1.4/bin:/usr/bin:/usr/ucb:/etc:.:/usr/sfw/bin:/usr/local/bin:/usr/ccs/bin"/>
                        <envvar name="LD_LIBRARY_PATH"
value="/opt/postgresql/8.1.4/lib"/>
                        <envvar name="PGDATA" value="/var/opt/postgresql/data"/>
                    </method_environment>
                </method_context>
        </exec_method>

        <exec_method
                type='method'
                name='stop'
                exec='/opt/postgresql/8.1.4/bin/pg_ctl stop'
                timeout_seconds='60'>
                <method_context>
                    <method_credential user='postgres' group='dba' />
                    <method_environment>
                        <envvar name="TMPDIR" value="/tmp"/>
                        <envvar name="PATH"
value="/opt/postgresql/8.1.4/bin:/usr/bin:/usr/ucb:/etc:.:/usr/sfw/bin:/usr/local/bin:/usr/ccs/bin"/>
                        <envvar name="LD_LIBRARY_PATH"
value="/opt/postgresql/8.1.4/lib"/>
                        <envvar name="PGDATA" value="/var/opt/postgresql/data"/>
                    </method_environment>
                </method_context>
        </exec_method>

Please, could you tell me why the pid file is not deleted on shutdown?

Thanks
Peter