Database connection object error?

Errpr msg: Can't append, object already in collection

I dealt with this msg before and I solved it, but today, my mind just doesn't work, help!

Code for ADO calling SQL Stored Procedure

Code:

---

Dim cmd As New ADODB.Command
    Dim prm As Parameter

    with cmd
    .CommandText = "MySP"
    .CommandType = adCmdStoredProc
    .Name = "MySP"
    Set prm = .CreateParameter("CID", adInteger, adParamInput, 4, lngID)
    .Parameters.Append prm
    end with

    Set cmd.ActiveConnection = MyConnection 
    'following more code here

---

last line is the problem. Myconnection is the connetion object already opened. I just can't figure out what could be wrong. Any suggestions are appreciated!