I thought of doing this as its own thread but since it's directly related to this decided against it.
This is not related at all. You have a crash, and although it seems like it's caused by this conversion, I can tell you for sure it is not. Converting two integers to float has never caused any crash.
Since you cannot provide relevant debugging information, there's nothing much we can do to help you. You should really learn how to get useful information from the debugger, needless to say that it will help you a lot in all your future projects
You should also provide a complete and minimal example that reproduces the problem. Nobody is interested in all your code, if the problem is only caused by a small part of it.