NSInternalInConsistencyException error when updating database

NSInternalInConsistencyException when i trying to insert data into my database, this are my code, anyone can help solve this error?

-(IBAction)SaveEasy:(id)sender{
NSString *Questions = Question.text;
NSString *Answers1 = Answer1.text;
NSString *Answers2 = Answer2.text;
NSString *Answers3 = Answer3.text;
NSString *Answers4 = Answer4.text;
NSString *CorrectAnswers = CorrectAnswer.text;
NSString *Hints = Hint.text;

NSString *sql = [NSString stringWithFormat:@"INSERT INTO EasyQuestion('Question','Answer1','Answer2','Answer3','Answer4','CorrectAnswer','Hint') VALUES ('%s', '%s', '%s', '%s', '%s', '%s', '%s')", [Questions UTF8String] , [Answers1 UTF8String], [Answers2 UTF8String], [Answers3 UTF8String], [Answers4 UTF8String], [CorrectAnswers UTF8String], [Hints UTF8String]];

char *err;
if (sqlite3_exec(db, [sql UTF8String], NULL, NULL, &err) !=SQLITE_OK){
    sqlite3_close(db);
    NSAssert(0, @"Could not update table)");
}else{
    NSLog(@"table updated");
}

Question.text = @"";
Answer1.text = @"";
Answer2.text = @"";
Answer3.text = @"";
Answer4.text = @"";
CorrectAnswer.text = @"";
Hint.text = @"";

}