Compile error: "User-defined type not defined"

I split my database (Access2k) and then went into the front end to test my forms, now I'm getting the compile error, the form has a multi list select box (which I got from this wonderful site) and then you press a button to preview a report, when I press the button the Visual basic debugger window appears and with the compile error:
On Error GoTo Err_cmdOpenQuery_Click
Dim MyDB As DAO.Database
Dim qdef As DAO.QueryDef
Dim I As Integer
Dim strSQL As String
Dim strWhere As String
Dim strIN As String
Dim flgSelectAll As Boolean
Dim varItem As Variant

Set MyDB = CurrentDb()
I read some of the previous threads regarding compile errors, but I'm still stuck. Hope someone can shad some light on this...

The error means the required references are not present for the declared variables in the project.

A2K and newer use ADO as the default. You have to explicitly add a reference to the DAO libraries if you want to use DAO. My recommendation is to convert your code to ADO