Using XL2007.

In code I open a text file (csv) and format it as I want it, then the
program saves the file using: ActiveWorkbook.SaveAs MyFullFileName

All runs fine. But, when I try to open the file, I get an error that says
the file is corrupt or has an unrecognizable file extension...what the?

This is using code I've used for years in 2003 without problem.

Any help would be appreciated.