Remarks，DB2 version is v10.5.0.3 ，the operating system is linux ia64。
When I used the toad 5.6 for DB2 LUW to connect the remote database,then the following error was jumping :
System.NullReferenceException
Object reference not set to an instance of an object.
Stack Trace:
at IBM.Data.DB2.DB2ConnPool.Open(DB2Connection connection, String& szConnectionString, DB2ConnSettings& ppSettings, Object& ppConn)
at IBM.Data.DB2.DB2Connection.Open()
at Quest.Toad.Db.Connection.OpenConnection(IDbConnection connection)
at Quest.Toad.DB2.DB2ToadConnection.OpenConnection(IDbConnection connection)
at Quest.Toad.Db.Connection.AllocConnection()
at Quest.Toad.Db.Connection.Connect(Boolean notify)
at Quest.Toad.Db.Provider.BackgroundConnector.CreateBackgroundConnection()