I tried to burn a multisession data cd.After some sessions of burning data when i try to burn some new data i get a message as below.

The disk you have inserted is not empty,but the writing mode of your compilation is 'start multisession' or no 'multisession'.This will cause the information already on the disk inaccesible via windows explorer.
Should Nero proceed with writing to this disk?

MY NERO VERSION IS 6.6.1.15
KINDLY PROVIDE SOLUTION