Forms :: Oracle 10g And Database Connection

Toady i have installed oracle forms 10g and oracle 10g db when i run my form it gives me this error how can i resolve it

"ora-12154 tns could not resolve the connect identifier specified"

View the image below:

Here are the values in forms 10g tns

# tnsnames.ora Network Configuration File: C:DevSuiteHome_1
etworkadmin nsnames.ora
# Generated by Oracle configuration tools.

EXTPROC_CONNECTION_DATA =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = localhost)(PORT = 1521))
[code].......

and here the values of forms 10g SQLnet

# sqlnet.ora Network Configuration File: C:DevSuiteHome_1
etworkadminsqlnet.ora
# Generated by Oracle configuration tools.

SQLNET.AUTHENTICATION_SERVICES= (NTS)

NAMES.DIRECTORY_PATH= (LDAP, TNSNAMES, EZCONNECT, ONAMES, HOSTNAME)
(description =
# (address=(protocol=tcp)(host=localhost)(port=1383))
(ADDRESS = (PROTOCOL = TCP)(HOST = localhost)(PORT = 1521))
(connect_data=(rpc=on))
)

What changes should i make to overcome this problem.