Hi Manoji,
in order to install in a multi-user environment you have to setup a LAN with a computer hosting the MySQL Server with the DB and all the other clients with just the software pointing to that server.
Also you have to set SINGLEUSER=no in the OpenHospital configuration files.
Useful informations are in the Administrator Manual:
http://sourceforge.net/projects/openhospital/files/AdminManual/v.1.7.1/