How big are these attachments? It looks like you're putting the entire content of <STDIN> to $str, and this might be causing the seg faults. I think the following (untested) code does what the code does, without consuming too much memory. Comments welcome. 
while (<>) {
    my $val='';
    if (/^\#:lav/) {
        $_.=<>;
        $val.="$_\n";
        while (/^#:eof/m) {
            $val.="$_\n";
            $_.=<>;
        }
    }
    print $val;
}

[download]
Update: fixed the bonehead error of using next inside the loops.

In reply to Re: weird perl verion and/or OS problem with newlines by asarih
in thread weird perl verion and/or OS problem with newlines by vinforget

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