Problem with a simple C app. Calloc

I'm making this simple C program.  I'm using Calloc to allocate space to hold an array containing the number of instances of each letter in the file.
Source: http://pastebin.com/G46Pr6Tg

When I try to Calloc, or Malloc then memset the memory, one of the items in the array is not initialised to zero.  This is part of the array straight after initialisation:
......
Number of f: 0
Number of g: 0
Number of h: 134777
Number of i: 0
Number of j: 0
......

What did I do wrong?

>>1
calloc
Found your problem. Write your own memory allocator.