Nero VisionExpress vob wrong length

Hello all,
I recorded my home videos onto a dvd using a stand alone LG DR4810 dvd recorder.
I want to copy some of the titles on to another dvd, so i copied all the .vob, .ifo,.bup files to my computer hard drive.
I then run Nero Vision Express and go to import the .vob files.
They appear in the window on the left but the lengths of the clips are all wrong…! They are all much too short.
If I put them on the time line they are also much too short.
For example if I import a 2min clip (title) Nero says the length is only 15 secs,
It’ll play only up to 15 secs, I know the clip is 2 mins long… and it plays properly in Powerplay…
Whats going on? Any help please…