Calling Oracle SP

I need to call a SP that needs to have three parameters passed, then one value returned...does someone have an example...this is the code I have so far...getting an unhandled exception error..

VB Code:

Dim recstatus As String 
        Dim objCommand As New OleDbCommand() 
 
        objCommand.Connection = objCon 
        objCommand.CommandText = "SP_PCMS_APPROVE_CARD" 
        objCommand.CommandType = CommandType.StoredProcedure 
        objCommand.Parameters.Add(New OleDbParameter("t_card", OleDbType.VarChar)).Value = "0378732582131001" 
        objCommand.Parameters.Add(New OleDbParameter("t_end_date", OleDbType.Date)).Value = Now 
        objCommand.Parameters.Add(New OleDbParameter("t_error", OleDbType.VarChar, 1)).Direction = ParameterDirection.Output 
        objCon.Open() 
        objCommand.ExecuteNonQuery() 
        recstatus = objCommand.Parameters(2).Value