iOS Question Error Compiling Hello World App

Ok, this has now happened 3 times ... and I am at a loss ...

I create a brand new B4I app, just the basic default template ... and it works. I click Button1 and Hello World pops up.

Then I change one thing ... it can even be this line:
And then it no longer compiles ... I get this error:

B4i Version: 8.51
Parsing code. (0.02s)
Building folders structure. (0.06s)
Running custom action. (0.06s)
Compiling code. (0.09s)
Compiling layouts code. (0.00s)
Compiling debugger engine code. (0.01s)
Building Xcode project. Error
Parameter is not valid.

Click to expand...

I am at a complete loss ... I've uninstalled the apps, re-done ... all the certificates for hours. Why does changing from the default then stop the compilation?