This seems like an operating system error, and indicates that the file you're trying to access is corrupt.
Files downloaded over the internet can get corrupted in case the network connection is not reliable or spotty.
You'll probably need to download again for this to work. Could you also tell us a bit about your computer/OS and the internet connection that you're using. For example, are you using Wireless or a wired connection. What is the speed on the internet connection. If its a slow and unreliable connection, downloading again may not solve the problem.