Multisession Error! :(

Hi There :smiley:

Iv been burning a DVD-R for ages now using the nero multisession option, adding another session every time I have a bit more data however iv just reached the end of the DVD and I came up with a burn error and now it will only let me view the first session of the disc and when I try to continue the multisession it says the disk it not writable, please help

Cheers Jeeves