The first error message, du: cannot access `~skim': No such file or directory, made me curious. I think that if you reduce your program to a very simple command you'll find that it's not running from the right directory or that ~skim doesn't exist? 
my $homedir = '~bogus';
$du=`du -ch $homedir`;
print "$du";

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produces a similar message for me: 
./test
du: cannot access `~bogus': No such file or directory
0       total

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In reply to Re: du with backticks by blahblahblah
in thread du with backticks by Panasonictoilet

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