this is the only fling trainer that windows block as virus

I use Avast Premier plus MalwareBytes (which calls the FBI if I sneeze) and both tell me there is nothing to worry about. I opened this trainer (just to be sure) and it is SAFE! 
Remember, most AV programs give false positives on trainers, because they do that same things that true virus software and malware does- change the properties and functions of another program. 
Lingon's trainers will sometimes install some weird crap in the /AppData/ directory, which gives reason for concern, but in over 16 years, I've never had problems with Fling's trainers.