could not create shared memory segment: Invalid argument

Hi,
I have just installed the latest version of OS X panther (10.3.3) and
am now getting the following error message:

postgres$ /usr/local/pgsql/bin/postmaster -i -D /usr/local/pgsql/data
FATAL: could not create shared memory segment: Invalid argument
DETAIL: Failed system call was shmget(key=5432001, size=10444800,
03600).
HINT: This error usually means that PostgreSQL's request for a shared
memory segment exceeded your kernel's SHMMAX parameter. You can either
reduce the request size or reconfigure the kernel with larger SHMMAX.
To reduce the request size (currently 10444800 bytes), reduce
PostgreSQL's shared_buffers parameter (currently 1000) and/or its
max_connections parameter (currently 100).
If the request size is already small, it's possible that it is
less than your kernel's SHMMIN parameter, in which case raising the
request size or reconfiguring SHMMIN is called for.
The PostgreSQL documentation contains more information about
shared memory configuration.

Any ideas on how i can resolve this issue?

many thanks in advance