Oracle 10G forms connection with Oracle database 10G Enterprise Edition in windows 7

I am trying to connect Oracle Forms 10g version (9.0.4) to the Oracle 10G Enterprise Edition.

At first I tried to connect to the db without setting the "Local Net Service Name Configuration" in Oracle Net Configuration Assistant.I got the error

After setting the "Local Net Service Name Configuration" in Oracle Net Configuration Assistant, I am still getting an error

Can anyone explain me how to connect to the database with forms as I am stubbed as of long struggle for connecting the database?

# tnsnames.ora Network Configuration File: C:\oracle\product\10.2.0\db_1\network\admin\tnsnames.ora
# Generated by Oracle configuration tools.

ORCL =
  (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = 127.0.0.1)(PORT = 1521))
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = orcl)
    )
  )

EXTPROC_CONNECTION_DATA =
  (DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1))
    )
    (CONNECT_DATA =
      (SID = PLSExtProc)
      (PRESENTATION = RO)
    )
  )

The following are the listener.ora and tnsnames.ora contents

# listener.ora Network Configuration File: C:\oracle\product\10.2.0\db_1\network\admin\listener.ora
# Generated by Oracle configuration tools.

SID_LIST_LISTENER =
  (SID_LIST =
    (SID_DESC =
      (SID_NAME = PLSExtProc)
      (ORACLE_HOME = C:\oracle\product\10.2.0\db_1)
      (PROGRAM = extproc)
    )
  )

LISTENER =
  (DESCRIPTION_LIST =
    (DESCRIPTION =
      (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1))
      (ADDRESS = (PROTOCOL = TCP)(HOST = RahulSingh-PC)(PORT = 1521))
    )
  )