C - warning: comparison between pointer and integer ('struct V_LISTE *' and 'int')

for simple chained (dynamic) list I want to write a function which deletes the first element which contains the char 'k'.

I´ve written the following function:

char popIfK(struct V_LISTE **kopf)
{
    char *returnVal;
    struct V_LISTE *kElement;
    kElement = *kopf;
    while (kElement->nachfolger != 'k')
    {
        kElement = kElement->nachfolger;
    }
    returnVal = &(*kopf)->vorname;
    free(*kopf);
    *kopf = kElement;
    return *returnVal;
}

In the while statement I get the warning: comparison between pointer and integer ('struct V_LISTE *' and 'int') while (kElement->nachfolger != 'k')

I have insert the elements with the function:

struct V_LISTE *insert(struct V_LISTE *list, char key)
{
    struct V_LISTE *newElement;
    newElement = (struct V_LISTE *) malloc(sizeof(struct V_LISTE));
    newElement->vorname = key;
    newElement->nachfolger = list;
    list = newElement;
    return list;
}

By calling it in main:

struct V_LISTE
{
    char vorname;
    struct V_LISTE *nachfolger;
};

int main()
{
    struct V_LISTE *kopf;
    kopf = (struct V_LISTE *) malloc(sizeof(struct V_LISTE));

    kopf->vorname = 'o';
    kopf->nachfolger = NULL;    kopf = insert(kopf, 'l');
    kopf = insert(kopf, 'k');
    kopf = insert(kopf, 'T');

    char name;
    name = popIfK(&kopf);
    printf("%c\n", name);
}

I run my program I get a segmentation fault: 11 I am not able to fi the problem and need some help please.