Message OCIEnvCreate failed with return code -1 but error message text was not available. Source System.Data.OracleClient Target Void .ctor(System.Data.OracleClient.OciHandle, HTYPE, MODE, HANDLEFLAG) Stack at System.Data.OracleClient.OciHandle..ctor(OciHandle parentHandle, HTYPE handleType, MODE ocimode, HANDLEFLAG handleflags) at System.Data.OracleClient.OciEnvironmentHandle..ctor(MODE environmentMode, Boolean unicode) at System.Data.OracleClient.OracleInternalConnection.OpenOnLocalTransaction(String userName, String password, String serverName, Boolean integratedSecurity, Boolean unicode, Boolean omitOracleConnectionName) at System.Data.OracleClient.OracleInternalConnection..ctor(OracleConnectionString connectionOptions) at System.Data.OracleClient.OracleConnectionFactory.CreateConnection(DbConnectionOptions options, Object poolGroupProviderInfo, DbConnectionPool pool, DbConnection owningObject) at System.Data.ProviderBase.DbConnectionFactory.CreatePooledConnection(DbConnection owningConnection, DbConnectionPool pool, DbConnectionOptions options) at System.Data.ProviderBase.DbConnectionPool.CreateObject(DbConnection owningObject) at System.Data.ProviderBase.DbConnectionPool.UserCreateRequest(DbConnection owningObject) at System.Data.ProviderBase.DbConnectionPool.GetConnection(DbConnection owningObject) at System.Data.ProviderBase.DbConnectionFactory.GetConnection(DbConnection owningConnection) at System.Data.ProviderBase.DbConnectionClosed.OpenConnection(DbConnection outerConnection, DbConnectionFactory connectionFactory) at System.Data.OracleClient.OracleConnection.Open() at xxx.FillDataset(String connectionString, CommandType commandType, String commandText, DataSet dataSet, String[] tableNames) in c:\inetpub\wwwroot\... \OracleHelper.cs:line 1344 at GetUserDetailsForUserForPwd(String strUserName, String StrUserPwd) in clsUsers.cs:line 31 at btnLogin_Click(Object sender, EventArgs e) in Login.aspx.cs:line 104 -----------------------second error Message ORA-06413: Connection not open. Source System.Data.OracleClient Target Void Check(System.Data.OracleClient.OciErrorHandle, Int32) Stack at System.Data.OracleClient.OracleException.Check(OciErrorHandle errorHandle, Int32 rc) at System.Data.OracleClient.OracleInternalConnection.OpenOnLocalTransaction(String userName, String password, String serverName, Boolean integratedSecurity, Boolean unicode, Boolean omitOracleConnectionName) at System.Data.OracleClient.OracleInternalConnection..ctor(OracleConnectionString connectionOptions) at System.Data.OracleClient.OracleConnectionFactory.CreateConnection(DbConnectionOptions options, Object poolGroupProviderInfo, DbConnectionPool pool, DbConnection owningObject) at System.Data.ProviderBase.DbConnectionFactory.CreatePooledConnection(DbConnection owningConnection, DbConnectionPool pool, DbConnectionOptions options) at System.Data.ProviderBase.DbConnectionPool.CreateObject(DbConnection owningObject) at System.Data.ProviderBase.DbConnectionPool.UserCreateRequest(DbConnection owningObject) at System.Data.ProviderBase.DbConnectionPool.GetConnection(DbConnection owningObject) at System.Data.ProviderBase.DbConnectionFactory.GetConnection(DbConnection owningConnection) at System.Data.ProviderBase.DbConnectionClosed.OpenConnection(DbConnection outerConnection, DbConnectionFactory connectionFactory) at System.Data.OracleClient.OracleConnection.Open() at FillDataset(String connectionString, CommandType commandType, String commandText, DataSet dataSet, String[] tableNames) in OracleHelper.cs:line 1344 at GetUserDetailsForUserForPwd(String strUserName, String StrUserPwd) in clsUsers.cs:line 31 at btnLogin_Click(Object sender, EventArgs e) in Login.aspx.cs:line 104