problem with outlook account

hi i m vijay

i m facing strange prblem ,i m new to network
in my domain i got maildelivery account.
we use post master/outlook for mails.
when i try to send or receive any mails from maildelivery it says that “you don’t have appropriate rights to perform this operation” when i close it then message pops up is that
“the file normal already exists, do you want to replace the existing file?
i had to cancel
i had checked security and all other posibilites
but in vain
if anyone can help me with i’ll grateful.

thanks in advanced to everyone