Oracle Database Discussions

Hi,
I can't to configure an IPC connection.
This is my listener.ora
LISTENER_IDMAS =
(DESCRIPTION_LIST =
(DESCRIPTION =
(ADDRESS_LIST = (ADDRESS = (PROTOCOL = IPC)(KEY = IDMAS))
)
)
)

SID_LIST_LISTENER_IDMAS =
(SID_LIST =
(SID_DESC =
(ORACLE_HOME = /oracle/ora_8.1.7)
(SID_NAME = IDMAS)
)
)

STARTUP_WAIT_TIME_LISTENER_IDMAS = 0
CONNECT_TIMEOUT_LISTENER_IDMAS = 10
TRACE_LEVEL_LISTENER_IDMAS = OFF
TRACE_DIRECTORY_LISTENER_IDMAS = /home/oracle/network/log
LOG_DIRECTORY_LISTENER_IDMAS = /home/oracle/network/log

This is my tnsnames.ora
IDMAS_IPC=
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = ICP) (KEY = IDMAS))
# (ADDRESS = (PROTOCOL = TCP) (Host = claa002q) (Port = 1521))
)
(CONNECT_DATA = (SID = IDMAS)
)
)

On start of listener_idmas, all is very well
Listening on: (DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=IDMAS)))

Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=IPC)(KEY=IDMAS)))
STATUS of the LISTENER
------------------------
Alias listener_idmas
Version TNSLSNR for IBM/AIX RISC System/6000: Version 8.1.7.2.0 - Production
Start Date 28-AVR-2004 17:48:23
Uptime 0 days 0 hr. 0 min. 0 sec
Trace Level off
Security OFF
SNMP OFF
Listener Parameter File /home/oracle/network/admin/listener.ora
Listener Log File /home/oracle/network/log/listener_idmas.log
Services Summary...
IDMAS has 1 service handler(s)
The command completed successfully

But I can't connect to my database
Attempting to contact (ADDRESS=(PROTOCOL=ICP)(KEY=IDMAS))
TNS-12538: TNS:no such protocol adapter
...
I don't understand.

Thank in advance for your help,
gnom92