Michael,

>in the meantime I started working with Visual Studio 2005 and MM.Net 2.1. I created a new business objects project and tried to test these classes in the test workbench. If I instatiate the aapptest-class I always get an error: "error instantiating class" (translated text of the german version!). If I click on details there is just an hex error code 0x80004005?!
>
>The business objects of this project are working correctly as a part of a windows forms solution. The project shows no errors when rebuilding the project.

Good to hear from you! Are you using VB .NET or C#? Unfortunately, VB .NET classes don't work as well with the Object Test Bench. Here are a few things to check:

1. Make sure your project builds without errors before trying to instantiate an object

2. Try instantiating the object from the Class View window instead...just right-click the object in the Class View window and select Create Instance

3. Try it on another computer...something might be wrong with the Visual Studio installation on your computer

Best Regards,