need help seg fault in pset5 speller

Question

all works fine but part way through the unload function I get

Program received signal SIGSEGV, Segmentation fault. 0xb7e929e5 in _int_free (av=0xb7fc9420 <main_arena>, p=0x8844168, have_lock=0) at malloc.c:3814
3814    malloc.c: No such file or directory.

my code for the unload function is:-

bool unload(void) 
{ 
    for(place = 0; place < 26; place++) 
    { 
        pointer = root; 
        checkArray(pointer); 
    } 
    return true; 
} 

void checkArray(node *pointer) 
{ 
    if (root->child[place] != NULL) 
    { 
        for (int i = 0 ; i < SIZE ; i++ ) 
        { 
            if (pointer->child[i] != NULL) 
            { 
                childNum = i; 
                current = pointer; 
                pointer = pointer->child[i]; 
                checkArray(pointer); 
                return; 
            } 
        } 
        free(pointer); 
        current->child[childNum]=NULL; 
        pointer = root; 
        checkArray(pointer); 
        return; 
    } 
    else 
    { 
        return; 
    } 
}

can anyone help