can't stat Permission denied

["M.Lucas" <mlucas@taos-it.nl>]

Hello,

I have a very strange error with 4 files on a squid proxyserver. 
(as root)

$  ls -al /var/spool/squid/00/27/
ls: /var/spool/squid/00/27/00002780: Permission denied
ls: /var/spool/squid/00/27/00002781: Permission denied
ls: /var/spool/squid/00/27/0000277D: Permission denied
ls: /var/spool/squid/00/27/0000277E: Permission denied
total 7
drwxr-xr-x    2 proxy    proxy         144 Nov 18 08:51 .
drwxr-xr-x  258 proxy    proxy        6192 Nov 18 08:55 ..

$ file  /var/spool/squid/00/27/00002780
/var/spool/squid/00/27/00002780: can't stat 
`/var/spool/squid/00/27/00002780' (Permission denied).
For the other I get similar results

$ lsattr /var/spool/squid/00/27/00002780
lsattr: Permission denied while trying to stat 
/var/spool/squid/00/27/00002780

$ rm -f /var/spool/squid/00/27/00002780
rm: cannot remove `/var/spool/squid/00/27/00002780': Permission denied

How can I delete these files?

With kind regards,
Met vriendelijke groet,

Maurice Lucas
TAOS-IT