encoding the film then using nero to burn it the problem it says is thet i am writing a multi session what does this mean? any help appreciated

If you write a multi session disk in Nero, it means you can add stuff to it later. The only problem with this is, Other people without Windows XP and some standalones, may not be able to read the disk.

If you have no intention of adding anything to the disk, it's best to burn without multi session, as this will be more widely compatible.

just don't do a multisession. Also finalize the disc.

yep, make sure the 'finalize disc' option is checked