關於DataEnvironment+DataReport的問題(編號:8768)

目前要寫讓使用者輸入日期就可以看營業報表....
選營業日報表後,輸入日期,卻告訴我"引數可能有類型錯誤或超過可接受的定義範圍,或與其他引數衝突",但是如果我單獨執行DataReport1就沒有問題.....
可否請大家幫我看一下錯誤在哪裡呢?
指令內容如下:
Private cn As ADODB.Connection
Private Sub BusinessDateForm_Click()
Dim cmd As ADODB.Command
Dim param As ADODB.Parameter
Dim ret As String
Dim Mysql As String
ret = InputBox("請輸入營業日報表的日期" _
& Chr(13) & "例如:2000/12/25", "營業日報表")
If ret = "" Then
Exit Sub
End If
ret = CStr(ret)
On Error Resume Next
Mysql = "select * from mealchargedata where date1='" & ret & "'"
Set cn = New ADODB.Connection
cn.Open "dsn=wangca;uid=sa"
Set cmd = New ADODB.Command
cmd.ActiveConnection = cn
cmd.CommandText = Mysql
Set param = New ADODB.Parameter
Set param = cmd.CreateParameter("prmstart", adDate, adParamInput)
cmd.Parameters.Append param
cmd.Parameters("prmstart").Value = DateValue(ret)
Set rs = New ADODB.Recordset
Set rs = cmd.Execute
Set DataReport1.DataSource = rs
DataReport1.Top = MDIForm1.Top + 3
DataReport1.Left = MDIForm1.Left + 3
DataReport1.Height = 8000
DataReport1.Width = 11600
DataReport1.Show vbModal
End Sub