Well, the problem with that file is that it's compressed or encrypted, I hope the first. I haven't been able to find the decompression type, so I'm asking for help here. The first link doesn't say anything about a compression, so I'm at a loss here...
Quick look at your file, we can see that it is an MPQ format version 1, so there's no HET and BET table, only the HashTable and BlockTable, both are encrypted, look in Fundamentals
for informations about hash theory, after decrypted you'll able to read the Flags that determined if the blocks/data are encrypted or compressed and what compression method is used.