It's a false positive, you can use it np, disable Avast for a moment, download it and run.
We're using it since a year, you can check it at
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There are only 5 positives on 50 AV and the result is generic/suspicious/possible malware. The truth these antivirus scanners are not reliable because they cant scan inside compressed files. Do this test: uncompress the exe and run again Avast, I bet you wont get any alarm.

Note: don't use it with new Mapinstall because it doesn't work.