One of the things I was worried about was that certain programs might see the .XLS extension and assume that it is an Excel spreadsheet, and therefore get confused. Maybe that's what's happening here?

>>Well, the thing I'm worried about is that a .XLS extension signifies that a file is an Excel spreadsheet, which means a binary file with a format specific to Excel. I know, I'm being picky.
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>Maybe you're not so picky. I've found one problem with this, and that is if you try to do an IMPORT from the DELIMITED file. You'll get an error.