star 1.5a25 (x86_64-redhat-linux-gnu): diff reports many different uname, gname

Hi,

We are doing our backup with star:
 
  star -c -v -time -acl H=exustar file=/dev/st0 \
        -not pattern=\*/\.recycle/\* /home \
        /root \
        /etc \
        /var \
        1>>$lf.log 2>>$lf.err
 
A verification is performed:
  star -diff -v -C=/ file=/dev/st0 1>>$lf.log 2>>$lf.err
 
This is the outcome (drawn from $lf.err):
star: 22101970 blocks + 0 bytes (total of 226324172800 bytes = 
221019700.00k).
star: Total time 5318.958sec (41553 kBytes/sec)
star: The following problems occurred during archive processing:
star: Cannot: stat 0, open 0, read/write 0. Size changed 0.
star: Missing links 0, Name too long 0, File too big 0, Not dumped 28.
star: Processed all possible files, despite earlier errors.
diffopts=perm,type,nlink,uid,gid,uname,gname,size,data,rdev,hardlink,symlink,sparse,mtime,ctime,dir 

star: WARNING: skipping leading '/' on filenames.
star: 22101970 blocks + 0 bytes (total of 226324172800 bytes = 
221019700.00k).
 
The verification stage reports more than 4000 errors of the following 
type (out of  350000 files)
home/commun/distribution/HP Laserjet 9050n/: different uname
      0 drwxrws---  :rwx/ntusers Mar 16 10:25 2007 
home/commun/distribution/HP Laserjet 9050n/
      0 drwxrws---  root/ntusers Mar 16 10:25 2007 
home/commun/distribution/HP Laserjet 9050n/
var/www/icons/pie2.png: different uname
    253 -rw-r--r--  root/rwx May 30 09:54 2001 var/www/icons/pie2.png
    253 -rw-r--r--  :rw-/rwx May 30 09:54 2001 var/www/icons/pie2.png
var/spool/mail/root: different uname,gname
   7660 -rw-------  root/:--- Mar 10 08:25 2007 var/spool/mail/root
   7660 -rw-------  :rw-/rwx Mar 10 08:25 2007 var/spool/mail/root
var/spool/samba/: different gname
      0 drwxrwxrwt  root/:--- Feb  8 18:07 2007 var/spool/samba/
      0 drwxrwxrwt  root/rwx Feb  8 18:07 2007 var/spool/samba/
    ...

What could be the cause of the problem (please note the strange 
user/group name reported) ?

Best regards