unable to add oracle driver connection

In new database connection.

name:oracle

driver:oracle.jdbc.driver.OracleDriver

dtabase url:jdbc:oracle:thin:10.10.20.20:1521:test

username:test

pasword:test

after that, i haveerror message;

unable to add connection, cannot establish a connection to jdbc:oracle:thin:10.10.20.20:1521:test using oracle .jdbc.driver.oracle driver.(Io exception:then network adapter could not establish the connection)

it was working before. I try to recreate the connection and have a problem

can you help me?

[559 byte] By [jin412a] at [2007-11-27 9:55:42]