Whoops, I'm amazed that I missed that

I am attempting to write a function with the following declaration: void OpenExcel(string filename, out Excel.ApplicationClass XLApp, out Excel.Workbook XLWorkBook, out Excel.Sheets XLSheets, out Excel.Worksheet XLWorkSheet) where the function will open an instance of excel and the workbook with the given filename, and assign the application instance, the workbook, the worksheets collection and the default worksheet to the variables passed in respectively When I attempt to compile I receive the following errors: Argument '2': cannot convert from 'Microsoft.Office.Interop.Excel.Application' to 'out Microsoft.Office.Interop.Excel.ApplicationClass' Argument '3': cannot convert from 'Microsoft.Office.Interop.Excel.Workbook' to 'out Microsoft.Office.Interop.Excel.Workbook' Argument '4': cannot convert from 'Microsoft.Office.Interop.Excel.Sheets' to 'out Microsoft.Office.Interop.Excel.Worksheets' Argument '5': cannot convert from 'Microsoft.Office.Interop.Excel.Worksheet' to 'out Microsoft.Office.Interop.Excel.Worksheet' This also fails when I replace "out" with "ref" Anyone know how to fix this?

ok, good to know, thank you.

So if I developed it on a machine using .NET 2.0, compiled it, and moved the EXE to a computer with .NET 1.1, it would fail?

If I write a program, say in C#, to read and write to a serial port and use the SerialPort class in .NET 2.0, will this program be compatible with machines still using .NET framework 1.1?