Getting the following error in stuido when I try to open a k2 black peral source file

Warning 1 Method 'PostFilterAttributes' in type 'SourceCode.Workflow.VisualDesigners.KPREditor' from assembly 'SourceCode.Workflow.VisualDesigners, Version=4.0.0.0, Culture=neutral, PublicKeyToken=16a2c5aaaa1b130d' does not have an implementation.  0 0