If an installer file was corrupted during the download (which can happen due to network errors, problems with download servers, or even anti-virus software on your computer), CrossOver will continue to use that corrupted file until you remove the installer cache and try another install of the given package/application.
Simply click "Edit" in Crossover and choose "Preferences". Now just click the "Clear" button.
How to clear the cache in older versions of Crossover