Instead of this:

my @args = ($ccupdate_db, "-ExcelFile $excel_file", "-q");
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Try this:

my @args = ($ccupdate_db, "-ExcelFile", "$excel_file", "-q");
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Anything that's separated by spaces is pretty much a separate argument as far as your OS is concerned, even though logically you have a sub-argument to an argument.

Also, make sure your web server has read access to the file. For that matter, since you're also uploading it, make sure it's getting written. Many CGI vs. command-line issues are related to permissions.