The software installer files can get modified or corrupted when you download them. We have seen problems where the IT department's firewall and/or virus software was corrupting the installer.
To verify that the AWRDE installer files have not been tampered with, you can verify the signature of the files yourself. Digital signatures are only available in AWRDE install files starting with version 7.53 and may not include 3rd party downloads (flexLM, testwave, etc.) that we provide.