I do pre-foreclosures all of the time and love it.In ga there is no right of redemption once it is sold at the courthouse steps it is gone for good.It sounds like the lender didn't know what the laws in your state were and was depending on you to know that for them.You being new didn't know any better.If you have a question in the future it is better to ask your prinicpal broker and get an answer than to not say anything and make a mistake.As far as the e&o policy covering you that is not always true it depends on what the principal brokers e&o policy says on the rider of what is covered and what is not.
The bank just holds paper and does not own the home until they have foreclosed on it and have the deed.Some states have right of redemtion,some allow for defeciency judgements,and some use a judicial,non-judical process or both.You really need to brush up on the laws of your state if you want to work this area.
good luck