Symptoms

When trying to edit the form in K2 Designer, it shows an error message saying

Server Error
Value cannot be null.
Parameter name: s
 

Diagnoses

We were able to determine that we need to rerun the configuration from the workflow for each Client Event pointing to the smartform.


 

Resolution

Before trying to apply the rollback approach described in the KB article you found, please try this first:

- edit your View and run through all the rules
- perform ‘configure’ for all the actions (step through the wizard, the workflows)
- please remember that you must redeploy the process in order for changes to be actually applied, so that the View definition can basically refresh the definitions of the rules and their actions.