This is usually caused by a missing field name in the Workflow Form permissions screen for the affected user. This means that the system doesn't know which column to use as it is missing or empty just like the error message states.
To check this:
Log into Forms Designer
Highlight the relevant form
Click Permissions
Find the affected user in the list
Ensure that they have the same "Record View Column" and "User View Column" as all working users and update if required
Click Save