This probably falls into the obvious category, but if you are using ORM and have code that sets the datasource in the ormsettings, it will not apply to basic cfquery calls.
//foo.cfc
var q = new com.adobe.coldfusion.query();
q.setSQL("select mediatype from media where media like :search");
var results = q.execute().getResult(); //ERROR!
//Application.cfc
this.ormEnabled=true;
this.ormSettings.datasource="monkeypower";
But - if you set this.datasource, it applies to both your cfquery calls as well as your ORM calls.
//foo.cfc
var q = new com.adobe.coldfusion.query();
q.setSQL("select mediatype from media where media like :search");
var results = q.execute().getResult(); //HAPPY MONKEYS!!
//Application.cfc
this.datasource="monkeypower";
this.ormEnabled=true;
I suppose you could use different values for each, but I'd bet most people are using one DSN and probably still use a few "basic" queries even when making use of ORM.