Upgrading to 7.3.1 problem

I am working on upgrading PostgreSQL from 7.2.1 to 7.3.1 on Windows. On the second installation step, I run into the 
following problem. 

$ initdb -D /usr/share/postgresql/data/
The files belonging to this database system will be owned by user "postgres".
This user must also own the server process.

The database cluster will be initialized with locale C.

Fixing permissions on existing directory /usr/share/postgresql/data/... ok
creating directory /usr/share/postgresql/data//base... ok
creating directory /usr/share/postgresql/data//global... ok
creating directory /usr/share/postgresql/data//pg_xlog... ok
creating directory /usr/share/postgresql/data//pg_clog... ok
creating template1 database in /usr/share/postgresql/data//base/1... IpcSemaphoreCreate: semget(key=1, num=17, 
03600) failed: Function not implemented

initdb failed.

Is the package I download incomplete? Or something else?

Thanks for your helps.

Vernon