谁能帮帮我啊Fatal NI connect error 12514

Fatal NI connect error 12514, connecting to:
(DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=121.10.142.19)(PORT=1521))(CONNECT_DATA=(SERVER=DEDICATED)(SERVICE_NAME=orcl)(CID=(PROGRAM=tlbb)(HOST=localhost.localdomain)(USER=root))))

  VERSION INFORMATION:
        TNS for Linux: Version 10.2.0.1.0 - Production
        TCP/IP NT Protocol Adapter for Linux: Version 10.2.0.1.0 - Production
  Time: 26-JUL-2008 15:52:24
  Tracing not turned on.
  Tns error struct:
    ns main err code: 12564
    TNS-12564: TNS:connection refused
    ns secondary err code: 0
    nt main err code: 0
    nt secondary err code: 0
    nt OS err code: 0



重启服务器后。可以链接,。大约运行5分钟就链接不了了。出现这个错误。,