Symptoms
When you compile your ADO project, you receive the following error:

Compile error:User-defined type not definedThis can occur on either a Connection or Command object.
Resolution
You may have referenced one of the following libraries instead of theMicrosoft ActiveX Data Objects (ADODB) type library:Microsoft ActiveX Data Objects Recordset (ADOR) type library.
-or-Microsoft ActiveX Data Objects (Multi-dimensional) (ADOMD) type library.