First off, while dvd decrypter remains a very useful application (particularly, in combo with AnyDVD for DLs), it is no longer being developed...as of 04/05, it is defunct. Consequently, it is not useful as a decrypter for recent releases. Either fab's or slysoft's applications will work just fine for decrypting, both are updated promptly when new copy protections are discovered. Both also offer free trials...you would do well to try them and see what you prefer.
Also when posting, it's helpful to give us specifics, such as the movie title as suggested in the second post. It allows for a more focused and concise response, and we wouldn't be wondering if this strictly a newer protection that dvdd can't handle or are there other issues at work here.
It sounds as though fab was able to rip the movie ok. Why not just burn the file to a rw?...and you should have your answer.
To answer your questions, I'm not completely certain, but to my knowledge...
A) Error reading/writing is configurable both within Fab Gold and within dvdd, I doubt that this is the case with freeware. My guess here is that the rip will fail re: "unreadable sector".
B) Again, my guess is no. I have not found enabling "ignore errors" with fab, particularly helpful, it simply fails.
Hope this helps.