my $filename = <"Hashstructure.txt">;

Not entirely sure if it has to do with your problem, but why are you using globbing to declare the file name?  As a consequence of the glob, the file name will include the double quotes. I would rather try a simple 

my $filename = "Hashstructure.txt";

[download]

Which OS are you using? Maybe it doesn't accept double quotes as part of a file name...

In reply to Re: filename flagged as Invalid argument by almut
in thread filename flagged as Invalid argument by Mr.Churka

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