SYMPTOM:
When trying to execute a predefined Freeform SQL report (including the reports located in the "Public Objects\Reports\Real Time Analysis" folder) in Strategy Enterprise Manager 9.x, the following error occurs :

QueryEngine encountered error: Connect failed. Error type: Odbc operation attempted: SQLDriverConect. Data Source name not found and no default driver specified

However, users may want to use another database instance for all reports that have been set at the project level, as shown below:

Changing the project level default database instance will not change the database instance that the Freeform SQL reports use. The Freeform SQL reports will use the default Strategy Enterprise Manager 9.x warehouse database instance. Since users really intend on using another database instance, the Strategy Enterprise Manager 9.x warehouse database instance will most likely not point to a valid database.
ACTION:
Edit the Freeform SQL definition of Freeform SQL reports and choose the appropriate database instance.