I'm having the same issue. The problem isn't located in the < div class="row text-center" >
The problem is in the lesson for < section class="container" >
I can get past entering this, but after that, when it asks you to enter two:
< div class="row" >
< /div >
This is where it gives the "invalid character" error. Must be a bug. I submitted a report yesterday, but I'm still having the same problem. I'd post my code, but it's identical to the one above.