objectsWhere crash

`

    NSArray *draftArray = [AWEVideoDraftModel objectsWhere:@"WHERE backup = 1 AND step > 0 AND step < 30 ORDER BY saveDate DESC" arguments:nil];  



#0Crashed: com.apple.main-threadEXC_BAD_INSTRUCTION 0x0000000000000000 Raw Text
--
0 |  | -[GYDataContext queueForDBName:] + 330
1 |  |  +[GYModelObject objectsWhere:arguments:] + 120

`

求大佬解答