failed to get audit u/s 44AB ...

friends,

my uncle is doing business of consignment agent i.e. get hire a  lorry for consignor to transfer the stock to consignee. From AY 06-07 he did n't file IT return. Turn over Rs. 41 lakhs. But there is no tax liability for that year. Due to TDS only refund will come.   My doubts are.

1. if he file return now for AY 06-07, penalty u/s 271F will come?

2. If he filed with out getting audit of his books of accounts , what are the liabilities?   (he is maintaining books of ac)

3. in case of NO tax liability,  whether refund claim will be affected due to late filing?

PLEASE HELP ME...