We're using Helpdesk Solution and recently ran into a situation where incidents (tickets) were assigned to workers who no longer exist, which must have caused the Helpdesk application to "lock" the incident. The worker name appeared as: "Error evaluating macro", and the owner appeared as: "Error evaluating macro".
To resolve this Problem, look into the database table "workitem" and into the field "number". Search for the article with the problem, and go to the field "updatelock". There is probably a "c" in that line. Delete the "c", close the database and you're back in business.