G'day Bindo,

See the documentation for the open function. Follow the example for opening a file for reading using three arguments and dying with a useful message when the open fails. Just because the file exists (i.e. -e is TRUE), doesn't mean you can read it (i.e. -r is not necessarily TRUE).

I'd also recommend you take a look at perlstyle: your code indentation is not at all logical which makes it hard to read and is a potential source or errors.