Sometimes a TIBCO Scribe® Online Solution generates a “Query is Null” fatal error if the Map is edited while the Solution is running.
 
Suggested Process: 
Best practice is never modify a Map when a Solution is in progress. 

1. Wait for the Solution to complete. 
2. If the Solution runs on a schedule, make note of what the schedule is, then change the solution to On Demand. 
3. Wait for the Solution to finish "preparing" and then open the Map you need to modify.  Save when your modifications are complete. 
4. Once you have modified the desired Maps, enable the Schedule again.