Problem with sprint_realloc_iteger()

I am implementing ethernetlike interface mib.I compiled the
MIB file using mib2c iterate_access.conf. I have used ioctl calls to
fetch the data and it is set in the get_first_data_item and 
get_next_data_item.
The problem is, when i use snmptable command, the code fails at
sprintf() statement in the sprint_realloc_integer() function.

case MODE_GET:
            switch (table_info->colnum) {
            case COLUMN_DOT3STATSINDEX:
        {
            long *index;
            size_t len;
            index = getIndex(data_context,&len);
                             smp_set_var_typed_value(var, ASN_INTEGER,
                                         (u_char *)index
                                         ,len);
        }
                break;

i am using net-snmp version 5.1.3

Thanks,
-Rashmi