Trying to install oracle apps VISION instance on linux server(64 bit) - Red Hat Enterprise Linux Ser

Hi gurus,
I am trying to install 'vision' instance on a single node virtual machine.  I downloaded all the zip files and unzip them and ran

./rapidwiz to start installation.   The installation started at stopped at one point to resolve the following items before continue.

1)Port Availability Check :
-- database node ports --
   RW-20006: Error: - Database Port value is not valid:  port value = 1521   DB ONS Local Port Value = 6300......  Available 
   DB ONS Remote Port Value = 6400......  Available 

Can some one help me how to clear this problem.   Also request, if this is not the right form, please move it to the right form.