Ubuntu – Problem with APTonCD application

I created a iso image using aptoncd & burned it to a dvd. Now when i tried to restore, the program does not detect the dvd in the drive. It shows "Please insert a disc in the drive." and if we click "ok" it shows E: Failed to mount the cdrom. The dvd is in the drive itself.

I tried sudo lshw -C disk and the output is:

*-cdrom
   description: DVD-RAM writer
   product: DVDRAM GH22NS50
   vendor: HL-DT-ST
   physical id: 1
   bus info: scsi@1:0.0.0
   logical name: /dev/cdrom
   logical name: /dev/cdrw
   logical name: /dev/dvd
   logical name: /dev/dvdrw
   logical name: /dev/scd0
   logical name: /dev/sr0
   logical name: /media/APTonCD
   logical name: /media/apt
   version: TN02
   capabilities: removable audio cd-r cd-rw dvd dvd-r dvd-ram
   configuration: ansiversion=5 mount.fstype=iso9660 mount.options=ro,relatime,uid=1000,gid=1000,iocharset=utf8,mode=0400,dmode=0500 state=mounted status=ready
 *-medium
      physical id: 0
      logical name: /dev/cdrom
      logical name: /media/APTonCD
      logical name: /media/apt
      configuration: mount.fstype=iso9660 mount.options=ro,relatime,uid=1000,gid=1000,iocharset=utf8,mode=0400,dmode=0500 state=mounted

Then i checked in disk utility application. in that dvd rom is shown as /dvd/sr0

My ubuntu version is 10.10.

Please help me to solve the problem.