Because of K2 Blackpearl Designer cannot be co-exist with .NET Framework 2.0 SP1 in the same machine, I have to uninstall VS2008, .NET framework 3.5, 3.0SP1, 2.0SP1. After it, I cannot open any K2 Project.
Error when open existing k2 project is the first Package Load Failture on SourceCode.VisualStudio.WorkflowPackage.
Error when Create new K2 Project is SourceCode.Configuration.ConfigurationManager threw an exception.