problem ripping bad subtitle

[Nimo]

Today i'm going to rip DVD and backup like usual but i notice something wried in my DVD.
- Robot4rip indicate that my DVD has ~7 GB of data eventhough my DVD is 4.5 GB(write on the label)
- WinDVD seem to be displaying subtitle fine.(playing from DVD)

I think it was ok. But it's wrong when i'm trying to encode it...
- I cannot extract *.sub from *.vob files. Vobsub show something errors on it.(while indexing files, It's show something like sector errors.)
- I cannot open *.sub files that i already extract(which indicate errors)
- I cannot load it into vobsub plugin. (in avisync and ffdshow as well)
- when trying to open *.sub using vobsub config. I found nothing in it..

I have no idea about this. It must be something wrong with DVD or bad-sector but r4r can rip it.
Any solution?

[ukendt]

Rip progs will show how much data the dvd is supposed to contain.
Now , if You , for instance, remove a couple of cells here and there, the dvd won't be of any use...still will rip progs tell you something else.
I made an error ripping Van Helsing on a dual( 8.5 Gb) and even if I needed 2 cells (about 12 min video an daudio) to be complete, the dvd was shown as complete, but when I played it I could easily see something was missing:(

[Nimo]

Bingo! I notice that when vobsub is indexing file. It's show an error at the last sector.(About 95%) So, I use DVD decrypter to rip every cell except the last one. And it's work!
Thanks