When your program is finished with a SQL-DMO object it created, you must release the object. After releasing your last reference to a SQL-DMO object, the object variable is invalid and must not be used. To use the object again you must get a new reference to it.
To release objects you created using the New keyword of a Dim statement or the CreateObject function, set the object variable to Nothing. For example:
Set oSQLServer = Nothing
Visual Basic will automatically release an object when the object variable goes out of scope.
Use the Release function to release objects you created using the OLE CoCreateInstance function. For example:
pSQLServer->Release();