Try referencing the workbook itself to see if it solves your problem

o = GETOBJECT(,'excel.application')
owb = o.ActiveWorkbook
owb.saveas(("c:\SamSludge.txt")

>My application will be called when Excel is up and a spreadsheet is visible. I need to save the spreadsheet as a text file. In testing my code I put the following in the command window (with the aid of Intellisense):
>
> myExcelApp = GetObject(, "Excel.Application")
> myExcelApp.ActiveWorkbook.SaveAs ("c:\SamSludge.txt")
>
>I get an error message from teh 2nd command saying that ActiveWorkbook does not evaluate to a object. Yet TYPE ("myExcelApp.ActiveWorkbook") returns "O". What did I do wrong?
>
>
>Tim