SQLServer Adapter Connection

Dear friends:

I’ve configured a connection to a SQLServer DB and I’m getting the following error. I’ve checked the SQLServer Administrator
and the instance is running correctly. If anyone knows what could cause this error it will be very helpfull.

Error encountered
[ART.118.5042] Adapter Runtime (Connection): Unable to enable connection resource adapterConnection:sqlServerConnection.
[ART.118.5036] Adapter Runtime (Connection): Unable to configure connection manager.
[ADA.1.204] Cannot connect to the database with DataSource class “com.microsoft.jdbcx.sqlserver.SQLServerDataSource”.
[Microsoft][SQLServer 2000 Driver for JDBC]The requested instance is either invalid or not running.

Things to check:
Confirm the port that sql server is running on - default is 1433

Confirm that either the server is running on the default instance or that your jdbc connection is specifically referencing the named instance of sql server. Named instances are common in clustered sql server configurations.

Confirm that the JDBC setup has been run on the sql server - otherwise it will not accept inbound connections from the MS JDBC provider

I’ve checked what you told me and everything is correct. Also I�m using a DB manager and I can create tables, etc. using that instance, so DB is working fine.
What else could be wrong?