createdb problem | issue

Hi,

I have successfully installed postgreSQL 7.2.1 on a Win2K machine.
Under cygwin, when I type:

    createdb testam

I get the following:

    ERROR:  CREATE DATABASE: source database "template1" is being
accessed by other users
    ERROR:  CREATE DATABASE: source database "template1" is being
accessed by other users
    createdb: database creation failed

Why does it happen?

Thanks,
Joao