Hi J_Verhoeven,
The encountered error is generated by a feature called "SmartScreen filter" and it’s designed to keep you safe from malicious programs.
If you are indeed using R77.30 you shouldn't receive the error in question. I have personally used the Web Visualization Tool without experiencing any problems.
As such, could you please check the following as it could be one of them at stake here:
1) Ensure you have downloaded the right package for the correct OS.
2) Switch to another admin account on your computer and see if the problem persists.
3) If all else fails, try disabling SmartScreen altogether as shown below and then try again:
I hope this helps.