bsddb3.db.DBError: (14, 'Bad address')

[HappyCustomers]

Traceback (most recent call last):
File "D:\Personal\bitcoin\walletool-master\walletool-master\wt_extract_keys.py", line 31, in
main()
File "D:\Personal\bitcoin\walletool-master\walletool-master\wt_extract_keys.py", line 19, in main
w_data = read_wallet_dat(args.filename)
File "D:\Personal\bitcoin\walletool-master\walletool-master\walletool\wallet_files.py", line 16, in read_wallet_dat
d.open(filename, 'main', db.DB_BTREE, db.DB_THREAD | db.DB_RDONLY)
bsddb3.db.DBError: (14, 'Bad address')

Getting the following error. please help