You're not looking at it from the point of view of taint checking. Taint-checking is telling you that one of the 2 arguments to bind (probably the second) is "insecure".

Looking at the source of Net::Printer, I now see the problem: Line 534 of Printer.pm is our old friend

    if (!(bind($sh, $this))) {
    return "Printer: Error: Cannot bind socket: $!\n";
    } # if !bind($sh, $this)
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Where does $this come from? Line 525 packs it, based on the contents of $thisaddr. That variable is set in line 512 from the return values of gethostbyname($hostname), and $hostname is set at line 500 by the insecure code chop ($hostname = `hostname`);.

It's potentially insecure because it uses a path lookup, and because the value is coming from outside your program. If you're very very sure that hostname will be returning a correct value, you can "untaint" $hostname by the methods discussed in this thread and in perlsec.

Better would be to modify the code to discover the hostname without running another process in backticks.