Oracle Database Discussions

hello,
I installed oracle 9i in my machine and is accessable from SQLPLUS . In the same drive i installed Report builder, i am getting the below error when i tried to connect DB from Report builder.

REP-0501: Connecting to the database not specified.
ORA-12521: TNS: address symbolic have not been resolved

I create 2 accounts "system/ensa2010" and "sys/mrs2010" and a DB "master"

to connect I use this informations
User: system
Password: ensa2010
Database: master


the contents of my tnsnames.ora file is:

# TNSNAMES.ORA Network Configuration File: C:\oracle\ora92\network\admin\tnsnames.ora
# Generated by Oracle configuration tools.

MASTER =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = toto-86fb8e5b52)(PORT = 1521))
)
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = master)
)
)

INST1_HTTP =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = toto-86fb8e5b52)(PORT = 1521))
)
(CONNECT_DATA =
(SERVER = SHARED)
(SERVICE_NAME = MODOSE)
(PRESENTATION = http://HRService)
)
)

EXTPROC_CONNECTION_DATA =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC0))
)
(CONNECT_DATA =
(SID = PLSExtProc)
(PRESENTATION = RO)
)



Please, if you have any ideas help and thanks.