I am very confusing with this new toy.. I am facing this error message : "Must Declare the variable '@mHostCode' .. when below codes run:

Try
Dim cmd As System.Data.OleDb.OleDbCommand
Dim mGetAccessTypeCode As String = "Select * from DialPrefix Where HostCode = @mHostCode AND PrefixNo = @mPrefixNo Order by HostCode, PrefixNo"
Dim DataReader As System.Data.OleDb.OleDbDataReader
OleDBConn1.Open()
cmd = New System.Data.OleDb.OleDbCommand()
cmd.CommandText = mGetAccessTypeCode
cmd.Parameters.Add("@mHostCode", SqlDbType.Char)
cmd.Parameters("@mHostCode").Value = pHostCode ' from paramater
cmd.Parameters.Add("@mPrefixNo", SqlDbType.Char)
cmd.Parameters("@mPrefixNo").Value = pPrefixNo ' from parameter
cmd.CommandType = CommandType.Text
cmd.Connection = OleDBConn1

DataReader = cmd.ExecuteReader
pATypeFound = DataReader.Read
If DataReader.Read Then
pATypeCode = DataReader.GetValue(4)
End If
OleDBConn1.Close()
Catch err As Exception
Message(err.Message)
Finally
OleDBConn1.Close()
End Try

please help me .. TIA

Best Regards
Winan