Thread: Segmentation fault!

Please do have a look at the attachment to get an idea of how it's supposed to look.

After opening a file, each line (containing <TITLE><space><PRICE><comma>) is read, and then a node is created which is to be inserted at a suitable (sorted) place. The relevant part of the code is:

Code:

typedef struct books {
    char title[TITLE_LEN];
    double price;
    struct books *nxt_price;
    struct books *nxt_title;
} booksT;


    // Each line is scanned, then 'insert' is called.
    for (i = 0, pos = 0; (feof(f) == 0); i++) {
        
        fseek(f, pos, SEEK_CUR);
        fscanf(f, "%s %lf", temp_title, &temp_price);
        insert(titles, prices, temp_title, temp_price);
        pos++;
    }

void insert (booksT *titles[26], booksT *prices[10], char tmp_title[], double tmp_price) {
    booksT *newnode, *runner;
    int index;
    
    newnode = (booksT*)malloc(sizeof(booksT*));
    if (newnode == NULL) {
        printf("Memory allocation error.\n");
        exit(1);
    }
    
    strcpy(newnode->title, tmp_title);
    newnode->price = tmp_price;
    
    // Placement according to title.
    index = newnode->title[0] - 'A';
    
    if (titles[index] == NULL) {
        titles[index] = newnode;
    }
    else {
        runner = (booksT*)malloc(sizeof(booksT*));
        if (runner == NULL) {
            printf("Memory allocation error.\n");
            exit(1);
        }
        
        strcpy(runner->title, newnode->title);
        runner = titles[index];
        
        for (runner = titles[index]; (runner->nxt_title != NULL) && (strcmp(runner->title, runner->nxt_title->title) < 0); runner = runner->nxt_title);
        
        runner->nxt_title = newnode;
        free(runner);
    }
    
    // Placement according to price.
    index = (int)newnode->price / 10;
    
    if (prices[index] == NULL) {
        prices[index] = newnode;
    }
    else {
        runner = (booksT*)malloc(sizeof(booksT*));
        if (runner == NULL) {
            printf("Memory allocation error.\n");
            exit(1);
        }
        
        runner->price = newnode->price;
        runner = prices[index];
        
        for (runner = prices[index]; (runner->nxt_price != NULL) && (runner->price < runner->nxt_price->price); runner = runner->nxt_price);
        
        runner->nxt_price = newnode;
        free(runner);
    }
}

Line 69 seems to be giving me a segmentation fault. Why would that be? Am I trying to insert the nodes incorrectly?