Pitfalls In Property Acutions?

I am a Singaporean working in Thailand for a few years now. My thai

girlfriend and I are thinking of getting a piece of land that is up for

auction at the LED of thailand. I assume the land was mortgaged and is up

for auction. My main concern is that if we are successful what are the

pitfalls that can awaits us before claiming ownership? Can we be

successful in bidding for the land and still unable to claim the land? I

mean could the owner refuse to give up the land or could other creditors

challenge the transfer? I am totally new at this and any suggestions and

advices will be most appreciated.