I have seen this occasionally, but not debugged it. As a quick exercise I checked the code:
Use of uninitialized value in numeric gt (>) at /usr/local/bin/durep line 502.
Use of uninitialized value in addition (+) at /usr/local/bin/durep line 506.
501 # If hard links > 1 then ensure we don't count this file more than once
502 if($s[3] > 1) {
503 next if($inodes{$s[0]}{$s[1]});
504 $inodes{$s[0]}{$s[1]} = 1;
505 }
506 %files->{SIZE} += $s[7] if(include_file($_, \@s));
507 %files->{COUNT}++;
so $s[3] (nlink) is not initialised, and probably (size) $s[7]
A wild guess is that lstat failed (477 @s = lstat $child;) although no idea why.
Maybe contact the contributor for this psc@saco-gmbh.de (see
http://no.longer.valid/phpwiki/index.php/Disk%20Usage%20Report )