If you have pop-up blockers enabled, you may see a warning from your browser asking you if you'd like to allow the pop-up. You need to allow the pop-up to download the export.
The file you download may be a compressed file, commonly known as a ZIP. After you decompress or unzip the file, you can open the files containing your survey results. If you're using a Windows computer, try using WinZip. If you're on a Mac, try using StuffIt Expander.
If you have anti-virus software enabled, this may interfere with your download and cause a message saying, "file is corrupt." You may need to disable the software to download the export.