This article was created in response to a support issue logged with K2. The content may include typographical errors and may be revised at any time without notice This article is not considered official documentation for K2 software and is provided "as is" with no warranties.
The following error appears when trying to register a site against a SharePoint environment, or when accessing Designer:
"Could not load file or assembly 'K2Field.K2Forms.Controls.Charting' or one of its dependencies. The system cannot find the file specified."
The issue was caused by a missing custom control DLL in C:\Program Files (x86)\K2 blackpearl\K2 SmartForms Designer\bin\ folder.
You can read more it in this reference.
To resolve the issue, copy the required DLLs into the folder