problem with ulimit

hi,
i cant set ULIMIT for normal user (file size more than 2gb).but in root user it is working fine.in user it is giving error like "limit exceeded (priviledged user)".

What shell those users use?
Look here if of any help
Managing Large Files on VxFS

http://uw714doc.sco.com/en/HANDBOOK/saT.ulimit.html

hi,
it ksh