Insert Query not working (FMDB)

Here is the code which I'm using to insert a record into a sqlite table

FMDatabase *dataBase = [self openDatabase];
    [dataBase open];
    if ([dataBase open] != YES) {
        NSLog(@"DB Error %d: %@", [dataBase lastErrorCode], [dataBase lastErrorMessage]);
    //VERY IMPORTANT
    }
    [dataBase beginTransaction];
    BOOL success= [dataBase executeUpdate:@"Insert into CrewUnits (pkCrewUnits,fkUnits,fkAgencyVehicles,fkLookupCodes_PrimaryRole, fkLookupCodes_LevelOfCare, PrimaryUnit) values (?, ?, ?, ?, ?, ?);", pkCrewUnits, fkUnits, fkAgencyVehicle, fkLookupCodes_PrimaryRole, fkLookupCodes_LevelOfCare, [NSNumber numberWithInt:1]];
    NSLog(success ?@"YES" :@"NO");
     NSLog(@"Error %d: %@", [dataBase lastErrorCode], [dataBase lastErrorMessage]);
   FMResultSet*resultSet= [dataBase executeQuery:@"select * from CrewUnits"];
    NSLog(@"ResultSet : %@", [resultSet resultDictionary]);
    [dataBase commit];
    [dataBase close];

Database Path

- (FMDatabase *)openDatabase
{

    NSLog(@"Open Database");
    NSString *documents_dir = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];
    NSString *db_path = [documents_dir stringByAppendingPathComponent:[NSString stringWithFormat:@"HPSix_05BD.db"]];    // DatabasePath
    FMDatabase *db = [FMDatabase databaseWithPath:db_path];
    if (![db open])
        NSLog(@"Failed to open database!!!!!");
    return db;
}

I'm using the same logic to fetch data from table that works fine for me. But I can't insert a record. I don't know what I'm doing wrong here.