Issue with OS X

Hi,
I am trying to install postgresql 8 on a G5 OS X machine and cannot get
past this error i have tried changing the shared buffer with no luck.

Error message:
/usr/local/pgsql/data postgres$ FATAL: could not create shared memory
segment: Invalid argument

DETAIL: Failed system call was shmget(key=5432001, size=10338304, 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 10338304 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.