The steps to resolve the case are:
1. Open the status transition in question. In example: status "Open" to status "Working in Progress" (if this is which is returning the error message)
Go to Administration tab > Service Desk > Incident/Request/Problem > Status Transition Incident
2. Look at the field "Condition". See if there is any condition set, and if that condition exists as a macro condition.
3. If not, you need to remove that condition and save the status transition.
4. In an specific case, the Condition field was empty, however in the in_trans table, the Condition columns was set as something like ("NULL") value.
This is not a valid NULL value. The valid NULL value is something like (""). So in this case, the value need to be change from "NULL" to "" in in_trans > Condition column. This can be done directly by an sql query, such as:
update in_trans set condition = "" where condition = "NULL"
After this query, you need to run the following commnad in a DOS prompt in the Service Desk server:
pdm_cache_refresh -t in_trans