Question on Crontab; unable to edit/list

[Abhijit Das <ADas yodlee com>]

Hi 

my linux kernel is 2.2.20 
i am trying to edit/list crontab [i also tried crontab -e -u root]
but i am getting this err msg:
You (root) are not allowed to use this program (crontab) 
See crontab(1) for more information

i checked /etc/cron.allow root and my other users are listed [fyi i am able
to edit/list crontab with my other users]
there is no cron.deny file

i checked /var/spool/cron and root is listed there. i can do a more root to
see my crontab entries. 
i checked the crontab file under /usr/bin , nobody has tampered with the
permissions or setuid bit. 

what else can cause this err msg to come ? 

can anybody help me please

thx
Abhijit