compile error:User-defined type not defined ,高手帮帮忙，必给分！

Dim iTp As Integer
Dim con As ADODB.Connection
Dim rs As ADODB.Recordset
Dim slSql As String
Dim i, j As Integer
Dim strBak(2) As String

Private Sub Form_Load()
Dim cnt As Integer

Set con = New ADODB.Connection
Set rs = New ADODB.Recordset
'"Provider=Microsoft.Jet.OLEDB.3.51;Persist Security Info=False;Data Source=C:\WINDOWS\Desktop\dataUse.mdb"
con.Open "provider=Microsoft.Jet.OLEDB.3.51; data source= " & App.Path & "\mybook.mdb"
rs.Open "select * from person", con, adOpenStatic, adLockOptimistic
If rs.RecordCount > 0 Then
rs.MoveFirst
displayInfo
CanSave (False)

Else
'new data
CanSave (True)
Call Command2_Click(0)

End If
Command1(0).Enabled = False
End Sub

****************
为什么我运行程序，
总是提示： compile error:
User-defined type not defined
出错行高亮显示为第2行。
到底什么原因？高手帮帮忙，必给分！