Excel problem with deleting CustomProperty in Korean

On a Korean OS I'm getting the following exception 开发者_如何学Cwhen trying to call the Delete() method on the CustomProperty object. I'm doing this in C# using the Office2003 PIA for Excel. This HRESULT isn't that helpful to me, can anyone help figure out what's going on here?

    "Exception from HRESULT: 0x800A03EC"} System.Exception {System.Runtime.InteropServices.COMException}

   at System.RuntimeType.ForwardCallToInvokeMember(String memberName, BindingFlags flags, Object target, Int32[] aWrapperTypes, MessageData& msgData)
   at Microsoft.Office.Interop.Excel.CustomProperty.Delete()