Compile error in visual studio 2015

[anonymous_user_864e4c7d1 (anonymous_user_864e4c7d)]

I followed this tutorial; - YouTube but at around 5:04 i get this error:

and when i click on yes (ja) i get this error;

what can i do to solve that issue

[anonymous_user_864e4c7d1 (anonymous_user_864e4c7d)]

i closed every instance of unreal and it worked