Property

I purchased/registered a land in tambaram/chennai of 2400 sq. feet in 2008 and in the same survey lot of apartments are coming up. i got it in 2008 from my previous owner who has registered his document in 1991. As per EC there is no other registration & no other owners. he was in possession of this land for 17 years and i am the owner of the property for 7 years. but the owner who is having the document registered in 1976 where the details of the survey are available in cents is given power to some other party now in 2014. Also now they are calling all the registered parties in the same survey to the special judge for verification. In this case I have some questions. 1. my registered document is still valid ? 2. Even some one before to 1991 document sold to this owner by earlier owner benomee/third persons, still my document is valid ? if there is any mistake, can I make a rectification deed with the registration office ? 3. I don't have patta, is that a problem? Kindly clarify the above points. Thanks & best regards Raja- chennai