When setting up the Persistent Variables extension you are free to create/use into another database than the recommended IpPbxExtensions database.
The Persistent Variables extension uses the IpPbxExtensions database by default.
If you use another database you need to tell the Persistent Variables extension the name of it.
This is done in the properties of the Run GSE Action block that loads the PersistentVariables GSE action.
Please note: it is highly recommended to use the suggested defaults for the database (local MS SQL Server, IpPbxExtensions database)!
Alternatively you can also use the 6.5 - Use different database configuration.