Why does Android drop files I transfer to SDCard while in recovery mode?
Try downloading the update.zip again to ensure it's not a bad download.
Try updating your version of ClockworkMod Recovery, i think the latest version for your phone is 6.0.3.1. Get into fastboot mode and ensure you have the drivers installed. You can flash this by downloading the relevant file and running the command
fastboot flash recovery &lt;recoveryfile&gt;
(replace  with the filename of the recovery you downloaded (eg recovery-clockwork-touch-6.0.3.1-crespo4g.img)


If that fails you could try flashing the factory image again. Download the factory image from here and unzip. There should be a flash-all.bat which will restore your phone to stock. Note that this operation deletes all user data by default. (although i guess you've already wiped so nothing left to delete!)