Have you checked the MD5 checksum of the download? Basically it checks the integrity of the file to make sure the download was corrupt/incomplete.

Download this: Download MD5 Checker 2.31 Free - A utility that can verify downloads with an MD5 checksum - Softpedia

Unzip it and use it to check the MD5 of what you've downloaded (on the phone if possible, you'll need to mount the phone as an external disk on the PC). There should be instructions in the zip file and the MD5 you want to check against is this

Code (Text):

1. 5A92C12C105D6B6A9CD48286A0131E7B

 

Try "fastboot erase cache".

If you downloaded the boot.img package and used the .bat file in that, then the erase cache command is included.