Symptoms

After upgrading the Smartforms Control Pack to 4.6.9, the Worklist Control displays the error "Unable to connect to server." Clicking on "Details" displays "Instance validation error: 'undefined' is not a valid value for ValueType."
 

Diagnoses

This was a pre-existing issue that was exposed by fixes that were added in 4.6.9, and only occurs when compound Worklist filters containing a logical operator were set up on the Worklist control. After the upgrade, the logical operator is cleared, resulting in this error.
 

Resolution

To workaround this error, edit the view or form with the worklist control, and reconfigure the filter to re-add the logical operator, which will be blank. Save and run the form or view, and the correct results will be returned.