OK, that is weird. After I read your reply I tried downloading and running it again - and was able to run it fine.
Then, I tried again, some time later - and was unable to run it, with the same error message, yet again.
I scanned the corrupted avastclear.exe file with Virus Total and got 4 FPs:
Then, I deleted the corrupted file and tried downloading again - and this time the program opened normally again.
I scanned the proper working file and got different results (only 2 FPs this time).
The file appears exactly the same in size (in Windows).
But something must be different. And, I found out, when I get downloading a corrupted file, it downloads faster.
It seems like it's unable to get properly to my PC, and when it takes couple seconds longer, I get the proper working file.
I've already run SFC /SCANNOW before and it's all good. And I have no malware on my PC. What could be the problem?