MaxDB Database Access problem!!!

I am trying to access a new datasource other than the default one. But when I do a simple select query application, it gives SQLException.

here below the exception caught. Can anyone figure out what could be the reason? I restarted J2EE server already.

ResourceException in method ConnectionFactoryImpl.getConnection(): com.sap.engine.services.dbpool.exceptions.BaseResourceException: SQLException thrown by the physical connection: com.sap.dbtech.jdbc.exceptions.JDBCDriverException: SAP DBTech JDBC: Cannot connect to jdbc:sapdb://server21/TST [Restart required].

thanks in advance

nikhil