DTS Custom Task

I am hoping someone can send me in the right direction...I am trying to export some information from a SQL Server into an Excel spreadsheet. I am able to successfully perform this task via the DTS Designer in SQL Server. However, when I try this technique programmatically in Visual Studio .NET, I come across an error of "System.InvalidCastException: QueryInterface for interface DTS.CustomTask failed". I have looked at samples, but none of the samples are .NET. Could anybody give me some info?