Oracle Developer Tools for Visual Studio

Hello,

I have a Visual Studio LightSwitch project where I connect to a Oracle server and select a view as a new data source.

I get a error message "Object reference not set to an instance of an object" after selecting the Oracle view as a data source.

The Visual Studio Log shows me following details in the ActivityLog:

362 End package load [Visual Studio Explorers and Designers Package] {8D8529D3-625D-4496-8354-3DAD630ECC1B} VisualStudio 2011/09/05 12:17:58.258
*363 ERROR OracleConnectionUIControl.ProcessParentFormAcceptButtonClick - Exception opening the connection. Oracle Data Provider for .NET ORA-12560: TNS: Fehler bei Protokolladapter at Oracle.DataAccess.Client.OracleException.HandleErrorHelper(Int32 errCode, OracleConnection conn, IntPtr opsErrCtx, OpoSqlValCtx pOpoSqlValCtx, Object src, String procedure, Boolean bCheck) at Oracle.DataAccess.Client.OracleException.HandleError(Int32 errCode, OracleConnection conn, IntPtr opsErrCtx, Object src) at Oracle.DataAccess.Client.OracleConnection.Open() at Oracle.VsDevTools.DDEX.OracleConnectionProperties.Test() at Oracle.VsDevTools.DDEX.OracleConnectionUIControl.ProcessParentFormAcceptButtonClick(Object sender, EventArgs e) {D601BB95-E404-4A8E-9F24-5C1A462426CE} Oracle Developer Tools for Visual Studio 2011/09/05 12:18:05.652*
364 OracleVSGPkg.QueryClose - Begin Oracle Developer Tools VS Package Query Close {D601BB95-E404-4A8E-9F24-5C1A462426CE} Oracle Developer Tools for Visual Studio 2011/09/05 12:18:32.001

But this error ORA-12560 does not make any sense, because I have got a working connection to the Oracle server and can see tables and views.

Any ideas?

Environment:
Visual Studio 2010 SP 1
Windows Server 2008 R2
ODAC 11.2.0.2.40 Beta 2 for Entity Framework and LINQ to Entities

Regards
Benjamin