This code: 
$value = $href->($key);

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should use curly braces (indicating that $hash is a reference to a hash), not parentheses (indicating that $hash is a reference to a function).

The line in question tries to call a subroutine referenced by $hash, hence the error message.

In reply to Re: error when passing hash as reference causes by dmitri
in thread error when passing hash as reference causes by ccarden

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